Magnesium allylmagnesium chloride

Mg. Li and co-worker first reported magnesium-mediated Barbier-Grignard allylation of benzaldehyde in water (Eq. 8.73).172 Recently, a study was completed in which some water-tolerant allylating agents were prepared in situ from allylmagnesium chloride and various metallic salts reacted with aldehydes in THF-FLO to afford the desired homoallylic alcohols.173... 

Reaction of methyl quinolinylsulfoxide (86) with allylmagnesium chloride or with 1-methylallyl-magnesium chloride led to the 2-allyl and 2-(l-methylallyl)quinoline, (87) and (88) respectively, contaminated with unseparable isomeric a,p-unsaturated derivatives, in high yields. ... 

Reaction of nonstabilized carbanions with [Fp(olefin)] complexes generally results in either displacement of the olefin or reduction of the metal rather than formation of stable (j -alkyliron complexes. This is especially true with simple, nonstabilized organo-magnesium halide or lithio reagents. However, allylmagnesium chloride and phenylmag-nesium chloride react in modest (20-40%) yield with the ethylene, propene and butadiene (1,4 addition) iron complexes. Lithium dimethylcuprate is even more efficient, reacting in up to 70% yield with Fp complexes of styrene, butadiene (1,4 addition) isoprene (1,4 addition) and allene. Complexes of cyclopentene and allene react in low... 

The addition of benzylmagnesium chloride to 130 at —78 °C is strongly influenced by chelation of the a-hydroxy center with the magnesium cation diastereofacial selectivity consistent with the Cram cyclic model therefore results in a 66% yield of the syn isomer 131 only. Interestingly, and for reasons not quite clear, the addition of allylmagnesium chloride proceeds with high diastereoselectivity to provide the anti isomer 133 as the major diaster-eomer (Scheme 31) [37]. 

Allylmagnesium chloride can be generated at — 78 °C from allyl chloride and magnesium powder in the presence of 2 mol % magnesium anthracene [46]. 

Other cyclization rearrangements were observed in the addition of allyl and methallyl Grignard reagents to butadiene (47). Intramolecular addition occurs after addition of a second butadiene [Eq. (17)]. With allylmagnesium bromide, three of four possible stereoisomeric hydrolysis products of the cyclized Grignard 21a were identified. With methallyl magnesium chloride, a cyclization product incorporating three butadiene molecules was also isolated. Further details have also been furnished... 

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