An Organocatalyzed Asymmetric Michael Addition of Cyclic Ketones to 1,3‐Diene‐1,1‐dicarboxylates

Abstract

The purely organocatalyzed direct Michael addition of cycloalkanones to 1,3‐diene‐1,1‐dicarboxylates was effected by a combination of (S)‐2‐(4‐toluenesulfonamidomethyl)pyrrolidine and acetic acid. Addition products were formed in high yield and with good regio‐, diastereo‐, and enantioselectivity. The catalysis took place through a dual activation mode, that is, a nucleophilic enamine activation of the donor ketone and an eletrophilic hydrogen‐bonding activation of the acceptor diene dicarboxylate. The addition products could easily undergo a stereoselective ketone reduction and subsequent lactonization to give compounds with high synthetic potential.