S(N)2' reaction of organozinc reagents activated by catalytic tBu-P4 base in the presence of LiCl.

The tBu-P4 base was found to be an excellent catalyst for the activation of organozinc reagents. The base was used to promote the S(N)2' reaction of alpha,beta-unsaturated esters bearing a gamma-chloride in the reactions with various organozinc reagents in the presence of LiCl. The reactions proceeded in high yield with excellent chemo-and regioselectivity. The role of LiCl appears to be the activation of the gamma-chloride of the alpha,beta-unsaturated esters, which was confirmed by NMR spectroscopic study.