Asymmetric construction of quaternary centers by enantioselective allylation: application to the synthesis of the serotonin antagonist LY426965.

[reaction: see text] Catalytic enantioselective allylation with a chiral bisphosphoramide was applied to the synthesis of LY426965, a serotonin antagonist. The key step, addition of a 3,3-disubstituted allyltrichlorosilane to benzaldehyde, provided the adduct containing a stereogenic quaternary center with excellent diastereoselectivity and enantioselectivity.