Synthetic Studies on the trans-Chlorocyclopropane Dienyne Side Chain of Callipeltoside A

Enantiomerically enriched trans-chlorocyclopropanemethanol was obtained by lipase kinetic resolution of dichlorocyclopropanemethanol 3, followed by reduction. The spsp2 bond of the trans-chlorocyclopropane dienyne side chain of callipeltoside A was constructed via a Stille coupling reaction of 1,1-dibromo-1-alkene 7 and a vinylstannane in a highly dipolar solvent capable of promoting HBr elimination to give internal alkynes.