anti-Selective, Catalytic Asymmetric Vinylogous Mukaiyama Mannich Reactions of Pyrrole-Based Silyl Dienolates with N-Aryl Aldimines
摘要:
Pyrrole-based silyl dienolates undergo asymmetric vinylogous Mukaiyama Mannich reactions with a series of N-aryl aldimines in the presence of the Hoveyda-Snapper amino acid-derived silver(I) catalysts. The Manrdch products alpha,beta-unsaturated delta-ammo-gamma-butyrolactams-are typically obtained in high yields, excellent gamma-site selectivities and anti-diastereoselectivities, and up to 80% enantioselectivity.
A practical, catalytic and enantioselective vinylogous Mukaiyama aldol reaction between 2-silyloxypyrrole donors and aromatic or heteroaromatic aldehyde acceptors is described. Using an enantiopure bisphosphoramide catalyst in conjunction with SiCl4, a variety of α,β-unsaturated-δ-hydroxylated γ-butyrolactam compounds were synthesized in high yields and with good to excellent levels of site-, diastereo-