Oxiranes reaction with organometallic reagents

Reaction with oxiranes (epoxides).2 Dimethylcopperlithium and diphenyl-copperlithium1 are more useful than other organometallic reagents for the nucleophilic ring opening of epoxides. Thus dimethylcopperlithium reacts with propylene oxide (equation 1) and 1,2-epoxybutane (equation 2) to give the expected secondary alcohols as the predominant products. 

Scheme4.68. Reactions of ethyl oxirane and styrene oxide with a variety of organometallic reagents [293, 302, 320].

For the sake of comparison, the regio- and stereo-selectivity of some nucleophilic openings of vinyl-oxiranes with organometallic reagents derived from copper, lithium, sodium and other metals indicate the control avail le under some conditions. Complete control of diastereoselectivity in the opening of cyclic vinyloxiranes is available, for example by utilizing palladium(0)-catalyzed conditions in the reaction of die sodium salt of dimethyl malonate with cyclic vinyloxiranes.Increased substitution on the vinyl portion of the vinyloxirane leads to isomerization with opening, as in the case of the disub-stituted vinyloxirane (150 equation 49). ... 

Scheme 8.96. The extension of a carbon chain by two carbon atoms as a consequence of the ring opening of an oxirane (epoxide, ethylene oxide) by the reaction with a representation of an organometallic reagent (benzylmagnesium bromide, a Grignard reagent), hydrolysis, and conversion of the resulting alcohol (3-phenyl-l-propanol) to the corresponding alkyl bromide (l-bromo-3-phenylpropane).

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