Organocatalyzed asymmetric vinylogous Michael addition of α,β-unsaturated γ-butyrolactam

Abstract

Highly efficient asymmetric vinylogous 1,6-Michael addition of α,β-unsaturated γ-butyrolactam to 3-methyl-4-nitro-5-alkenyl-isoxazoles and Michael addition to trichloromethyl ketones by using a chiral quinine-derived squaramide organocatalyst were described, giving products with high diastereo- and enantioselectivities (up to >25 : 1 dr and 96% ee).