Highly Diastereo- and Enantioselective Organocatalyzed Michael/Oxa-Michael Sequence: Asymmetric Synthesis of Pyranonaphthoquinone Derivatives

Abstract

An efficient asymmetric synthesis of pyranonaphthoquinones via Michael addition and oxo-Michael cyclization sequence of 2-hydroxy-1,4-naphthoquinone with (E)-2-nitroallylic acetates has been developed. The synthetically useful chiral pyranonaphthoquinone derivatives were obtained in moderate to high yields and high enantioselectivities. This approach offers a facile way to prepare chiral pyranonaphthoquinone derivatives with a wide range of functional group tolerance.