Diols reaction with organolithium reagents

The reaction of butyllithium with 1-naphthaldehyde cyclohexylimine in the presence of (/C )-l,2-diphenylethane-1,2-diol dimethyl ether in toluene at —78 °C, followed by treatment with acetate buffer, gave 2-butyl-1,2-dihydronaphthalene-l-carbaldehyde, which was then reduced with sodium borohydride in methanol to afford (1 R,2.S)-2-butyl-1 -hydroxymcthyl-1,2-dihydronaphthalene in 80% overall yield with 91 % ee83. Similarly, the enantioselective conjugate addition of organolithium reagents to several a,/J-unsaturated aldimines took place in the presence of C2-symmetric chiral diethers, such as (/, / )-1,2-butanediol dimethyl ether and (/, / )- ,2-diphenylethane-1,2-diol dimethyl ether. 

The Corey-Winter reaction proceeds with complete stereospecificity by a syn elimination pathway, allowing the stereospecific synthesis of alkenes. Thus, anti-1,2-diphenylethane-1,2-diol was converted into cis -stilbene (2.45), whereas the corresponding syn-diol gave irans -stilbene. The strained fi-cyclooctene was prepared from the Z-isomer using this procedure (2.46). An alternative stereospecific route to alkenes proceeds from the diol with ethyl orthoformate or WA(-dimethylformanude dimethyl acetal, or by conversion of the diol to a 2-phenyl-1,3-dioxolane and treatment with an organolithium reagent to promote proton abstraction at C-2 and... 

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