Synthesis 2003(7): 1018-1024
DOI: 10.1055/s-2003-39162
PAPER
© 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;
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Publikationsverlauf

Received 20 February 2003
Publikationsdatum:
09. Mai 2003 (online)

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] ).

1

DRL Publication No. 284.

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1

DRL Publication No. 284.

13

Oximes were prepared by reacting the corresponding carbonyl compounds with excess of hydroxylamine in methanol, either at r.t. or when required under heating (55 °C).