CLUSTER	Synlett 2006: 0133-0136   DOI: 10.1055/s-2005-922783
© Georg Thieme Verlag Stuttgart · New York
Phosphorodiamidic Acid as a Novel Structural Motif of Brønsted Acid Catalysts for Direct Mannich Reaction of N-Acyl Imines with 1,3-Dicarbonyl Compounds
Masahiro Terada*, Keiichi Sorimachi, Daisuke Uraguchi
Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku, Sendai 980-8578, Japan Fax: +81(22)7956602; e-Mail: mterada@mail.tains.tohoku.ac.jp;
Received 7 October 2005

Abstract

Phosphorodiamidic acid 1 was developed as an efficient Brønsted acid catalyst for the direct Mannich reaction of N-acyl imines with 1,3-dicarbonyl compounds. Phosphorodiamidic acids were proposed as a novel structural motif of enantioselective ­Brønsted acid catalysts because they possess unique features, including the capability of introducing various substituents to the nitrogen atoms and the preparation from readily available chiral diamines in a short step. We demonstrated that chiral phosphorodiamidic acid 1b derived from binaphthalene bis(sulfonamide) functioned as an enantioselective catalyst to give the Mannich product in an optically active form.

Key words

organocatalyst - Mannich reaction - green chemistry - asymmetric catalysis - imines