Alkenes reaction with Grignard reagents

Osmium tetroxide, reaction with alkenes, 235-236 toxicity of, 235 Oxalic add, structure of, 753 Oxaloacetic acid, structure of, 753 Oxetane, reaction with Grignard reagents, 680 Oxidation, 233, 348 alcohols, 623-626 aldehydes, 700-701 aldoses, 992-994 alkenes, 233-236 biological, 625-626 phenols, 631 sulfides, 670 thiols, 668... 

Sn2 reaction of allylic phosphates. The regioselective reaction with Grignard reagents provides a new access to alkenes. 

The reaction of (Z)-l-halo-l-alken) halides results in /S.y-unsaturated ketoo Displacement reactions. I.3-Dibr allyltrimethylsilane by reaction with Grignard reagents to effect chain elongj bromine and protodesilyation, it consii... 

Stereoselective alkene synthesis starts from the reaction of triethylsilyloxirane 117 with an organocuprate reagent and is concluded by oxidation of the formed P-silyl alcohol to the aldehyde, whose reaction with Grignard reagent and elimination of [EtjSi/OH] leads to either the ( )- or the (Z)-alkene (118 or 119) by using different reagents (Schane 7.45). 

Methods of synthesis for carboxylic acids include (1) oxidation of alkyl-benzenes, (2) oxidative cleavage of alkenes, (3) oxidation of primary alcohols or aldehydes, (4) hydrolysis of nitriles, and (5) reaction of Grignard reagents with CO2 (carboxylation). General reactions of carboxylic acids include (1) loss of the acidic proton, (2) nucleophilic acyl substitution at the carbonyl group, (3) substitution on the a carbon, and (4) reduction. 

Other papers of interest in this section report transamination of camphor-3-carbothioamides with secondary cyclic amines, reaction of camphorquinone with dimethyl /S-ketoglutarate, the use of fenchone (212 X=0) in alkene formation from Grignard reagents, bromination of 2-e/itfo-6-endo-dibromobornane to yield 2,3,6-endo-tribromoborn-2-ene, and camphor-enol trimethylsilyl ether formation by quenching the reaction mixture of butyl-lithium and camphor tosyl-hydrazone with trimethylsilyl chloride. ... 

Uncatalyzed addition reactions of Grignard reagents with nonconjugated alkenes and aUcynes are of limited use in synthesis. However, carbon-carbon double bonds substituted by a leaving group, such as an acetate, are susceptible to be displaced by organomagnesium compounds presumably by an addition-elimination pathway. A few examples have been reported (equation 64). 

Reaction of ketone dithioacetals with Grignard reagents opens synthetic routes to a variety of substituted alkenes (Scheme 14) . For the reactions of simple aliphatic dithioacetals the presence of a Ni-trialkylphosphine catalyst is needed . 

Vinylphosphonium bromide 208 reacts with Grignard reagents, forming alkylphospho-nium ylides. These ylides react with aldehydes, giving alkenes in a one-pot sequence. In this reaction, catalytic amounts of both copper and silver salts are necessary (equation... 

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