[reaction: see text] Alkynylboronates derived from 3,3'-disubstituted-2,2'-binaphthols react with various N-acylimines to give the expected chiral propargylamides with up to 99% ee. This new methodology was applied to the first enantioselective synthesis of the antitubulin agent (-)-N-acetylcolchinol.

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A series of acyclic allylic alcohols of general structure R(1)CH==CHCH(OH)R(2) were resolved by Sharpless kinetic resolution. The hydroxyl groups of these enantiomerically enriched alcohols were derivatized to diethyl phosphates, and the derivatives were reacted with organocopper reagents. Cleanest substitution reactions were observed with reagents R(3)(2)CuCNLi(2). With R(1) = Me and R(3) = n-Bu, the size of R(2) affected both the regioselectivity and stereoselectivity of the displacement. Larger R(2) groups gave higher regio- and stereoselectivities: with R(2) = 3-pentyl, >98% S(N)2' regioselectivity and >98% anti stereoselectivity were observed. Bn(2)CuCNLi(2) gave stereoselectivities comparable to those observed with n-Bu(2)CuCNLi(2) but t-Bu(2)CuCNLi(2) exhibited much lower diastereofacial preference.

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[reaction: see text]. A chiral derivative of tributylstannylmethanol, readily prepared from L-valine, undergoes Sn-Li exchange to provide an alpha-alkoxyorganolithium that adds to aldehydes with up to 91:9 dr. The diastereoselectivity depends on the solvent and alkyllithium used for transmetalation. Treatment of adducts with acid allowed recovery of the chiral auxiliary and diol with complete stereochemical integrity.