Development and Application of a Direct Vinyl Lithiation of cis-Stilbene and a Directed Vinyl Lithiation of an Unsymmetrical cis-Stilbene

[reaction: see text] The vinyl deprotonation of cis-stilbene can be readily achieved using s-BuLi in THF at -25 degrees C. The generated 1-lithio-1,2-diphenylethene undergoes an in situ Z-to-E isomerization, and subsequent reaction with electrophiles results in an efficient stereoselective synthesis of trisubstituted alkenes. A directed vinyl lithiation of the unsymmetrical cis-stilbene 2-styryl-phenyl-carbamic acid tert-butyl ester can be achieved regioselectively, thereby expanding this methodology for further synthetic applications in indole chemistry.