Haloalkanes and Alcohols

Robert J. Ouellette , J. David Rawn , in Organic Chemistry, 2014

Grignard Reagents

Haloalkanes and other compounds with the element of group vii cantlet bonded to either sp3-hybridized or sptwo-hybridized carbon atoms (aryl and vinyl halides) react with magnesium metal to yield organomagnesium halides called Grignard reagents . Grignard reagents are usually prepared in diethyl ether (CH3CH2O─CH2CHiii). An ether solvent is essential for the reaction. The French pharmacist Victor Grignard discovered this reaction in 1900, and it has been studied and used extensively always since.

Grignard reagents grade hands from 1°, ii°, and three° alkyl halides, although their reactivities differ. Aryl and vinyl halides react somewhat more slowly, and the cyclic ether tetrahydrofuran (THF) is required to prepare Grignard reagents of these compounds. The higher boiling indicate of the cyclic ether provides more vigorous reaction conditions, just the charge per unit of the reaction also increases considering THF solvates the Grignard reagent improve than diethyl ether.

Molecular model of a complex of methyl-magnesium chloride, a Grignard reagent, in which two molecules of tetrahydrofuran, THF, are bound to magnesium. The model is based on the crystal structure.

The order of reactivity of the halogens in haloalkanes is I   >   Br   >   CI >   >   F. Organofluorides are so unreactive that they are never used to gear up Grignard reagents. Organohalogen compounds containing bromine and chlorine are readily bachelor, and are usually used to set Grignard reagents. Grignard reagents are used synthetically to form new carbon–carbon bonds. A Grignard reagent has a very polar carbon–magnesium bond in which the carbon atom has a partial negative accuse and the metal a partial positive accuse.

The polarity of the carbon–magnesium bond is opposite that of the carbon–element of group vii bond of haloalkanes. Because the carbon atom in a Grignard reagent has a partial negative charge, it resembles a carbanion, and it reacts with electrophilic centers such as the carbonyl carbon cantlet of aldehydes, ketones, and esters. We will discuss this chemistry extensively in afterward chapters.

Grignard reagents react rapidly with acidic hydrogen atoms in molecules such as alcohols and water. When a Grignard reagent reacts with water, a proton replaces the halogen, and the product is an alkane. The Grignard reagent therefore provides a pathway for converting a haloalkane to an alkane in two steps.

Problem nine.7

Devise a synthesis of CH3CHiiCHDCHiii starting from 1-butene and heavy h2o (D2O).

Sample Solution

Reaction of a Grignard reagent, RMgBr, with D 2O will yield R─D. The necessary Grignard reagent is obtained from the respective bromoalkane, RBr.

The required ii-bromobutane tin can be prepared from 1-butene past adding HBr. This reaction occurs according to Markovnikov'due south dominion, and a hydrogen atom adds to the less substituted carbon atom of the double bond.

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Alcohols

Robert J. Ouellette , J. David Rawn , in Organic Chemistry, 2014

15.10 Alcohol Synthesis Using Grignard Reagents

Haloalkanes and aryl and vinyl halides react with magnesium metal to yield organomagnesium halides chosen Grignard reagents . An ether solvent, usually diethyl ether, is required for grooming of Grignard reagents. The French pharmacist Victor Grignard discovered this reaction over a century ago in 1900. Grignard reagents are powerful tools for the synthesis of alcohols.

A Grignard reagent has a very polar carbon–magnesium bond in which the carbon atom has a partial negative charge and magnesium has a partial positive accuse. Because the carbon atom in a Grignard reagent has a partial negative accuse, it resembles a carbanion, and it reacts with electrophilic centers such as the carbonyl carbon atom of aldehydes, ketones, and esters. We will discuss this chemistry in the side by side section.

Grignard reagents form easily from i°, 2°, and 3° alkyl halides. Aryl and vinyl halides react somewhat more than slowly, and the cyclic ether tetrahydrofuran (THF) is often used to ready Grignard reagents of these compounds. The higher boiling signal of the circadian ether provides more than vigorous reaction conditions, just the rate of the reaction is also increased because THF solvates the Grignard reagent amend than diethyl ether. The solvent, either diethyl ether or THF, is an essential component of the reaction.

Grignard reagents react rapidly with acidic hydrogen atoms in molecules such as alcohols and h2o. When a Grignard reagent reacts with water, a proton replaces the halogen, and the product is an alkane. The Grignard reagent therefore provides a pathway for converting a haloalkane to an alkane in ii steps. If the second step of this process is carried out in D2O, deuterium is introduced into the compound at the position initially occupied by the halogen.

Synthesis of Alcohols Using Grignard Reagents

Grignard reagents add together to carbonyl compounds to give primary, secondary, and tertiary alcohols. A primary alcohol is synthesized by reacting the Grignard reagent, R′─MgX, with formaldehyde.

Reacting a Grignard reagent with an aldehyde gives a secondary alcohol.

Reacting a Grignard reagent with a ketone gives a 3rd alcohol.

Limitations of the Grignard Reaction

We recollect that Grignard reagents cannot be made if acidic functional groups are too present in the halogen compound. The Grignard reagent is destroyed by reaction with acidic hydrogen atoms of h2o, alcohols, phenols, or carboxylic acid groups.

For the same reason, nosotros must consider the structure of the carbonyl compound selected for reaction with a Grignard reagent. If the carbonyl compound likewise contains a hydroxyl group, the fastest reaction will be the devastation of the added Grignard reagent by protonation.

Booze Protecting Groups

Many ways have been devised to protect acidic groups, such as an hydroxyl group, that would interfere with Grignard reactions. I of the simplest is conversion of an alcohol to a silyl ether.

To prevent the production of HCl, the reaction is carried out forth with an amine goad, which is converted to an ammonium table salt.

After the booze has been protected, a Grignard reaction is possible. In the 2nd footstep of the reaction, when the magnesium salt is hydrolyzed, the silyl ether is hydrolyzed likewise.

Acetylenic Alcohols

Alkynide ions react with carbonyl groups in much the same way as Grignard reagents practise. Nosotros call back that these ions are effective nucleophiles that will displace a halide ion from an alkyl halide to give an alkylated alkyne. The alkynides are prepared in an acid–base reaction with acetylene or a last alkyne using sodium amide in ammonia. If a carbonyl compound is then added to the reagent, an alcohol forms afterward acid work-up. If the alkynide is derived from acetylene, an acetylenic alcohol forms.

We can as well produce alkynides without using liquid ammonia. We recall that alkynes are more acidic than alkanes. Therefore, the acrid–base reaction of an alkyne with a readily available Grignard reagent gives a Grignard reagent of the alkyne. This alkynide ion of the Grignard reagent reacts with carbonyl compounds.

Trouble 15.20

The European bark protrude produces a pheromone that causes beetles to congregate. Draw 2 means that the compound could be synthesized by a Grignard reagent.

Problem xv.21

Write the structures of the 2 products obtained by reaction of 4-tert-buty1cyclohexanone with sodium acetylide. Predict which one is obtained in the larger corporeality.

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Ethers and Epoxides

Robert J. Ouellette , J. David Rawn , in Principles of Organic Chemistry, 2015

ix.four The Grignard Reagent and Ethers

Ethers such as diethyl ether or tetrahydrofuran are fantabulous solvents for sure reagents that would otherwise react with protons supplied by protic solvents. I such instance is the Grignard reagent , represented equally R—Mg—X, which can be prepared from haloalkanes too as from aryl halides.

The oxygen cantlet of diethyl ether (or THF) forms a complex with the magnesium cantlet of the Grignard reagent. These reagents in ether solution are very usefUl in organic synthesis.

The French chemist Victor Grignard received the Nobel Prize in 1912 for developing the methods to set these organomagnesium compounds. In a Grignard reagent, the R grouping may exist a 1°, ii°, or 3° alkyl group as well as a vinyl or aryl grouping. The element of group vii may exist Cl, Br, or I. Fluorine compounds practice not form Grignard reagents.

A Grignard reagent has a very polar carbon-magnesium bond in which the carbon atom has a partial negative accuse and the metal a partial positive charge.

This bond polarity is opposite that of the carbon-element of group vii bond of haloalkanes. Because the carbon atom in a Grignard reagent has a partial negative charge, information technology resembles a carbanion, and it reacts with electrophiles. Grignard reagents are very reactive reactants that are used synthetically to grade new carbon-carbon bonds. Nosotros will discuss these reactions in Section 10.6.

Grignard reagents react chop-chop with acidic hydrogen atoms in molecules such every bit alcohols and water to produce alkanes. Thus, formation of the Grignard reagent followed by reaction with h2o provides a manner to convert a haloalkane to an methane series in ii steps.

Problem ix.three

Devise a synthesis of CHthreeCHtwoCHDCH3 starting from one-butene and "heavy h2o" (DtwoO).

Solution

Reaction of a Grignard reagent R—MgBr with D 2O yields R—D. The necessary Grignard reagent is obtained from the corresponding bromoalkane R—Br.

The required ii-bromobutane can be prepared from 1-butene by adding HBr. This reaction occurs according to Markovnikov'due south dominion; that is, a hydrogen atom adds to the less substituted carbon atom of the double bond.

Trouble ix.4

Devise a synthesis of the following compound starting from benzene.

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Synthesis: Carbon with Ii Heteroatoms, Each Attached by a Unmarried Bail

Christopher Thou. Barber , in Comprehensive Organic Functional Grouping Transformations, 1995

4.xiv.ii.one.one.(iii).(b) By addition of a Grignard reagent to a vinylsilane

Grignard reagents volition add to vinyl silanes to generate the respective α-magnesiosilyl alkanes ( Equation (85)). As with the training of α-lithiosilyl alkanes above, the reaction is sensitive to the reagents used. Skilful yields for addition to the vinyl grouping were only achieved with either chloro or alkoxide groups on siliconsingle bondpresumably as a effect of reducing the electron density of the double bail. Deportation of the halide or alkoxy grouping on silicon but became significant when either a primary Grignard reagent was used or more than ane halide or alkoxy group was present <70JA7424>. Amino groups on silicon accept as well been shown to facilitate the Grignard reagent addition <84TL1905>. The addition of Grignard reagents to trimethyl(vinyl)silane has been reported when forcing weather condition were used <84CB383>.

(85)

Intramolecular addition of a Grignard reagent to a vinyl silane gave a highly diastereoselective synthesis of the cyclopentane ( 289 ) which could exist quenched in high yield with an electrophile (Equation (86)) <85TL2101>.

(86)

The improver of an organomagnesium reagent to the silylated α,β-amidate anion of ( 290 ) resulted in the generation of an α-magnesio-α-silylamide (Scheme 60). The normal 1,2-improver of the Grignard reagent to the carbonyl group was suppressed by the α-anion generated during the reaction. As with the addition of organolithium reagents described above, the reaction was sensitive to substitution on the β-carbon of the vinylic group <93JOC7474>.

Scheme threescore.

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Synthesis: Carbon with No Attached Heteroatoms

Alan Armstrong , in Comprehensive Organic Functional Group Transformations, 1995

ane.07.three.2.three.(ii) Organomagnesiums

Grignard reagents usually undergo 1,2-improver to α,β-unsaturated carbonyl compounds, simply there are examples where particular structural features of the substrate, specially steric hindrance in the region of the carbonyl grouping, cause sectional 1,4-addition. Northward,N-Disubstituted cinnamides were reported as long ago as 1905 to react with Grignards in this style <05MI 107-01>. An interesting example of this, highlighting as well the differing reactivity of Grignard reagents compared with organocuprates, is seen in the addition to amide ( xx ) (Scheme 23) <83TL5089>.

Scheme 23.

A major advance in the history of cohabit add-on was the report by Kharasch and Tawney that the addition of catalytic amounts of copper(I) salts acquired Grignard reagents to undergo i,iv-addition to isophorone (Equation (41)) <41JA2308>. While this process was widely used for many years, it was oftentimes unreliable, and has largely been superseded by the use of stoichiometric organocopper reagents.

(41)

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Synthesis: Carbon with Two Heteroatoms, Each Attached by a Single Bail

David T. Macpherson , Harshad K. Rami , in Comprehensive Organic Functional Group Transformations, 1995

four.04.three.2.ii.(i) With organometallic reagents

Grignard reagents react with orthoformates to provide aldehyde acetals by deportation of an alkoxy grouping ( Equation (73)). Alkyl, aryl, alkynyl, vinyl and heterocyclic Grignard reagents have all been employed, and the reaction is generally carried out in refluxing diethyl ether with yields ranging from fair to skilful <B-70MI 404-03>. The mixed ortho ester ( 76 ) prepared from triethyl orthoformate and phenol <70CB643> reacts with a broad multifariousness of Grignard reagents at room temperature and in higher yields than standard ortho esters <81JCR(G)4016>. Treatment of ( 76 ) with acetylenic Grignard reagents in dichloromethane allowed the grooming of some sensitive acetals (Equation (74)), <84JOC2031>. Allyl and propargyl aluminum reagents react with orthoformates or trimethyl orthoacetate at −lxxx   °C to class unsaturated acetals <86CB1725>. Organocuprates <84TL3075> and allylsilanes <89S128> also react readily with ortho esters in the presence of Lewis acids. The reaction of alkynes with ortho esters catalysed by zinc salts <58JA4607, 63OSC(iv)801> is an alternative to Equations (73) and (74) for the grooming of acetylenic acetals (Equation (75)). Although this method allows access to ketone acetals, it requires a pressure vessel for the reaction of volatile alkynes.

(73)

(74)

(75)

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Alkaline metal Globe Organometallics☆

T.P. Hanusa , in Reference Module in Chemistry, Molecular Sciences and Chemical Engineering, 2014

Chiral Grignard reagents

Grignard reagents that are chiral at the metal should give strong asymmetric induction, and if their chirality is controlled, they could accept not bad potential in stereoselective syntheses. There are likewise possibilities for studying single-electron transfer (Set up) in the reaction of Grignard reagents, in which the metal-begetting carbon is the just stereogenic center. In club to avoid the free-radical reactions that would thwart the synthesis of such species, the α-chloro- and α-bromoalkyl Grignard reagents (R)-BrMgCHXCH iiPh (10   =   Cl, Br), with >   97% ee were generated past a sulfoxide Mg commutation reaction from the enantiomerically and diastereomerically pure sulfoxides, p-ClC6H4Southward(O)CHCXCHiiPh. These Grignard reagents are configurationally stable at −   78   °C, but racemization occurs   ≥   −   60   °C, specially when the solution contains bromide ions. In the absence of halide ions, the configurational stability extends to −   twenty   °C. 112 A review 113 documents how the asymmetric synthesis of the related Grignard reagent ((S)-1-benzylpropylmagnesium chloride) (eqn [ix]) was used every bit a probe to examine the extent to which SET is involved in reactions of organomagnesium reagents, including amination, 114 allylation, 115 , 116 oxidation, 117 and transmetallation. 118

[9]

The Grignard reagent (South)-PhCH2CH(MgCl)CH2CHiii, in which the magnesium-bearing carbon atom is the sole stereogenic center, adds to CO2, PhNCO, PhNCS, and certain aldehydes with full retention of configuration. In contrast, reaction with benzophenone, electron-deficient aldehydes, and several allyl halides proceeds with fractional or complete racemization. The findings reflect a competition betwixt concerted polar and stepwise SET reaction pathways. 115 3-Iodoenoates are converted into the corresponding alkenylmagnesium species with complete retention of configuration of the double bail; both direct reaction and copper(i)-mediated reactions (via CuCN(2LiCl)) with diverse electrophiles (due east.chiliad., PhCOCl, Me3SnCl, ethyl ii-(bromomethyl)prop-2-enoate) provide polyfunctional enoates. 119

The majority of Grignard reagents are four-coordinate, merely the cis-isomers of octahedral complexes would be useful in the study of stereoselective synthesis. Six-coordinate octahedral Grignard reagents, (thienyl)MgBr(dme)ii and (vinyl)MgBr(dme)ii, were prepared every bit racemic mixtures of d- and 50-cis-isomers and characterized with X-ray crystallography. They are stereochemically rigid in toluene solution, but were not enantiomerically resolved. 120 The accented asymmetric syntheses of the d and l enantiomers for both cis-[MgBr(four-MeC6Hfour)(dme)2] and cis-[MgMe(dme)2(THF)]I have been accomplished. Subsequent reaction with RCHO (R   =   Pri or Ph) yields the respective alcohol in up to 22% ee. The enantiomeric Grignard reagents crystallize separately but racemize in solution; at −   60   °C, the racemic species crystallize. 121 Three chiral species cis-[MgBr(R)(dme)two] (R   =   Prdue north, Pri, allyl) take been prepared and characterized with Ten-ray diffraction; all are racemic. The isolation of trans-[MgBr2(tmen)2] and cis-[MgBr2(dme)2] indicates that bidentate third amine bases are less suitable for the preparation of cis-octahedral compounds, only the structures of cis-[MgBrii(triglyme)] and [Mg2(μ-Br)2(triglyme)two][Mgtwo(μ-Me)iiBr4] suggest that triglyme may be well suited for this purpose. 122

Optical action retention is observed in the course of the formation of the Grignard reagent from optically active (+)-R-1-chloro-1-phenylethane and Mg in EtiiO. 123 Treatment of the latter with Mg in Et2O and then with MethreeCOD gives 88% (+)-Southward-PhCHDMe in 6.ii% optical yield. 123

Later on quenching with DtwoO or ButOD, analysis of the products from the Grignard reagents formed from PhCHXMe (10   =   Cl, Br, I) in the optically active solvent –(R)-two-methoxypentane leads to the determination that Grignard reagent formation occurs on the Mg surface within a solvent cage by a one-electron transfer mechanism. 124

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Main-Grouping Elements, Including Noble Gases

T.P. Hanusa , ... Northward.R. Rightmire , in Comprehensive Inorganic Chemistry Two (Second Edition), 2013

1.37.four.ii.ii.1.2 Grignard reagents and related complexes

Grignard reagents are normally represented by the simple formula RMgX (R  =   organic group, X   =   halogen), although solvation, dismutation, aggregation, and deviations from this stoichiometry are mutual. Despite extensive piece of work in the expanse, equally documented in previous reviews, 310–313 the mechanisms of Grignard reagent formation are still nether study. The many variables involved, including the identity of the substrates, the nature of the solvents used, and the concrete grade of the magnesium, greatly complicate the research. Both radical and anionic pathways have been implicated in Grignard formation. 314 Grignard formation is found to be dramatically affected past the presence of magnesium halides 315 and iron(II) chloride. 316 Several books and reviews on Grignard reagents, stressing applications in organic synthesis, 317–319 and the chemistry of highly functionalized organomagnesium reagents 320 accept been published.

Schlenk equilibrium 321 (eqn [16]) occurs normally with many Grignard reagents, especially in ethereal solvents, merely deliberate manipulation of the equilibrium can affect the progress of reactions and the product distribution. Di- or polyfunctionalized Grignard reagents remain comparatively rare, although they can offering enhanced reactivity relative to their monofunctional counterparts RMgX; their chemical science has been reviewed elsewhere. 322

[16]

For over a century afterwards the initial reports of Grignard chemistry, it was uncritically causeless that the high reactivity of the magnesium–carbon bond mandated the use of anhydrous experimental conditions. This supposition was disproved in the case of Barbier–Grignard allylation of aldehydes (eqn [17]). 323 In dry THF, the reaction between benzaldehyde, allyl bromide, and Mg gain quantitatively, but when the water content in THF reaches vii%, the reaction stops. When smashing water is the solvent, all the same, the allyl halide is plain confined to the magnesium surface considering of hydrophobic interactions, shielding the metal from the water. The allylation reaction then proceeds, merely with low conversion. The reaction of allyl bromide or iodide with benzaldehyde and Mg in 0.ane   North aqueous HCl or NH4Cl again produces quantitative conversion of the aldehyde to allylation and pinacol coupling products. Such aqueous systems have received additional investigation, 324, 325 as aqueous Grignard chemistry is bonny for its utilize of an environmentally benign solvent; it has been the bailiwick of several reviews. 326–330

[17]

Grignard reagents that are chiral at the metal should give strong asymmetric consecration, and if the chirality were controlled, they could have bang-up potential in stereoselective syntheses. There are also possibilities for studying single-electron transfer (SET) in the reaction of Grignard reagents, in which the metal-bearing carbon is the but stereogenic center. Reactions in which Set is involved include amination, 331 allylation, 332, 333 oxidation, 334 and transmetallation. 335 This chemistry has been reviewed elsewhere. 336

The bulk of Grignard reagents are iv-coordinate, but the cis isomers of octahedral complexes would exist useful in the written report of stereoselective synthesis. A diversity of such systems are known 337, 338 ; as an example, the absolute asymmetric synthesis of the d and fifty enantiomers for both cis-[MgBr(4-MeChalf dozenHfour)(dme)2] and cis-[MgMe(dme)two(thf)]I has been accomplished. Subsequent reaction with RCHO (R   =   (i-Pr) or Ph) yields the corresponding alcohol in up to 22% enantiomeric excess. 339

Determination of the structures of Grignard reagents continues to be of interest, and reviews on this discipline have been published. 340, 341 Most of the structure authentications are done on crystalline materials, although solution studies performed with extended 10-ray absorption fine structure (EXAFS) spectroscopy are also available. Halide-bridged structures are common 342, 343 ; for example, the Grignard compounds MeMgBr and EtMgBr were found to be dimers in (n-Bu)twoO at both room temperature and −   85   °C. 344

The traditional uses of Grignard reagents in organic synthesis are documented in many references outside this affiliate. 317–319 There are numerous cases in which a Grignard reagent is used as a source of magnesium or as a ligand transfer reagent. In many reactions, the products are not organometallic species (e.thou., phosphoranes, 345 alkoxides 346 ) and are not detailed here.

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Horizons in Sustainable Industrial Chemistry and Catalysis

Matilde V. Solmi , ... Walter Leitner , in Studies in Surface Science and Catalysis, 2019

two.ane.ane Grignard Reagents

Grignard reagents (RMgX, X  =   halogen, R   = alkyl or aryl) are highly agile nucleophiles. They were reported to actuate CO2 to carboxylic acids already in the 1900s, past Grignard [45]. Unfortunately, their high reactivity limits the possibility of using substrates with functional groups (electrophiles), which would react faster with the Grignard nucleophile leading to a low chemo-selectivity in the desired carboxylic acid. All the same, their high activity allows their transformation in carboxylic acids under mild conditions such equally 1   bar of COtwo and room temperature [46] and the development of a continuous catamenia processes [47]. Dowson reported an analysis from which it was concluded that the synthesis of acetic acid starting from CH3MgX and captured CO2 was estimated to exist economically feasible, with costs comparable to those of well-established processes [48]. However, the Grignard reagents should be regenerated by electrolysis of MgX2 salts obtained equally by-products of the reaction, requiring extremely high amounts of energy to be obtained from renewable resources at low cost. Furthermore, the handling of Grignard reagents on the scale of majority chemicals is prohibitive with current technologies for safety reasons. Therefore, such a process would not follow the Green Chemistry principles, despite the use of CO2 equally feedstock.

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Synthesis: Carbon with Two Heteroatoms, Each Attached by a Single Bail

Max J. Gough , John Steele , in Comprehensive Organic Functional Group Transformations, 1995

four.08.2.2.ii Beryllium or magnesium

Grignard reagent analogues derived from sulfones have been known since the 1930s, and tin be synthesized by the reaction of a sulfone with a Grignard reagent. For example, Field treated methyl phenyl sulfone with ethylmagnesium bromide, and obtained the magnesio derivative in approximately xc% yield ( Equation (85)) <52JA3919>. Simpkin's book contains a useful summary of this chemical science <B-93MI 408-01>. The first report of an α-sulfenyl alkylmagnesium reagent was by Normant and Castro, who prepared benzylthiomethylmagnesium chloride from the corresponding chloromethyl sulfide in THF in 50% yield <64CR(259)830>. Afterwards, Sakurai and co-workers obtained a Grignard reagent from chloromethyl methyl sulfide by treatment with magnesium activated with iodine and dibromoethene <67CC889>. A black solution was obtained which reacted with TMS-Cl to give ( 127 ) in 33% yield (Scheme 49). The procedure was optimistically hailed by the authors as a useful synthetic method. Much later, Ogura and co-workers modified the reaction conditions (essentially past controlling the temperature between x   °C and xx   °C) of Sakurai'south experiment, and obtained the same Grignard reagent in yields above 90% (by titration) <82CL1697>.

(85)

Scheme 49.

Seebach and co-workers take described what amounts formally to an α-thio magnesium species. They transmetallated the thioacrolein dianion, originally prepared from thioacrolein with two equivalents of n-butyllithium (encounter Section four.08.1.2.ane.i), with magnesium bromide, whereupon subsequent reactions with electrophiles were confined to the α over the γ position <76AG(E)437>.

The but report of an α-thio beryllium species is past Yamamoto <87BCJ1189>, who obtained ( 128 ) in 89% yield upon mixing the ylide ( 129 ) with beryllium chloride in THF (Equation (86)).

(86)

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