Nickel(II)-Catalyzed Cascade Vinylogous Mukaiyama 1,6-Michael/Michael Addition of 2‑Silyloxyfuran with N‑Sulfonyl-1-aza-1,3-dienes: Access to Fused Piperidine/Butyrolactone Skeletons

An unprecedented and highly efficient nickel-catalyzed cascade vinylogous Mukaiyama 1,6-Michael/Michael addition of 2-silyloxyfuran with N-sulfonyl-1-aza-1,3-dienes is reported, in which 2-silyloxyfuran was successfully employed as nucleophile and electrophile sequentially. This methodology combined with subsequent reduction provides a facile access to biologically important fused piperidine/butyrolactone skeletons in good yield with exclusive diastereoselectivity under mild reaction conditions.