PAPER	Synthesis 2003: 1018-1024 DOI: 10.1055/s-2003-39162
© Georg Thieme Verlag Stuttgart ˙ New York
Triphenylphosphine Catalyzed Michael Addition of Oximes onto Activated Olefins [1]
Debnath Bhuniya*, Sankar Mohan, Sanju Narayanan
Metabolic Disorder (Chemistry) Group, Discovery Research SBU, Dr. Reddy's Laboratories Limited, Miyapur, Bollaram Road, Hyderabad 500050, India Fax: +91(40)23045438; e-Mail: debnathbhuniya@drreddys.com;
Received 20 February 2003

Abstract

A new reaction condition for Michael addition of oximes onto activated olefins has been discovered using a catalytic amount of triphenylphosphine. This is a first and milder alternative to classical base (hydroxide, alkoxide) catalyzed Michael addition of oximes. Various aldoximes 1a-h and ketoximes 2a-c (Figure [1] ) were reacted with different Michael acceptors such as ethyl acrylate, acrylonitrile, phenyl vinyl sulfone, methyl vinyl ketone, and 1-nitrocyclohex-1-ene to obtain the corresponding Michael adducts. About 35 different examples were attempted (Table [1] and Scheme [1] ); except in six cases where reactions did not produce desired products, yields varied from good to excellent. Reactions without triphenylphosphine did not proceed. A plausible mechanism of catalytic action in the present reactions is proposed (Figure [2] ).

Key words

Michael additions - oximes - alkenes - phosphorus - catalysis

1

DRL Publication No. 284.