Sequential organocatalytic Stetter and Michael-Aldol condensation reaction: asymmetric synthesis of fully substituted cyclopentenes via a [1 + 2 + 2] annulation strategy.

A stereoselective synthesis of fully substituted cyclopentenes has been achieved by a sequential organocatalyzed Stetter and Michael-aldol condensation of aromatic aldehydes, nitroalkenes, and α,β-unsaturated aldehydes via the [1 + 2 + 2] annulation strategy with excellent diastereoselectivities and enantioselectivities (up to >99% ee).