Mechanism and Stereoselectivity of the Phosphinylation of 3-Acyl Coumarins-Stereocontrol Via Concurrent Aromatic Interaction/Oxaphosphole Formation

Authors: Petrov, Petar Y.; Vassilev, Nikolay G.; Angelova, Silvia E.; Shivachev, Boris L.; Petrov, Galin P.

Source: Letters in Organic Chemistry, Volume 6, Number 2, March 2009 , pp. 180-185(6)

Publisher: Bentham Science Publishers

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Abstract:

Racemic P-acetoxy-P-chloro phenylphosphonite reacts with prochiral 3-acylcoumarins yielding (2R,3R)/(2S,3S)-coumarino-3,4-c-2-oxo-2-phenyl-1,2-3H-oxaphospholes with >99% regio- and diastereoselectivity. The stereoselectivity is governed by the presence of phophonite phenyl group and oxaphosphole ring formation. The product has suitable conformation providing stereoselective route to (R,S)/(S,R) phosphino-substituted coumarins, normally inaccessible by the Phospha-Michael reaction employing achiral reagents.

Keywords: Phosphonylation; phosphinylation; diastereoselectivity; dynamic NMR; kinetics; oxaphospholes

Document Type: Research article

Publication date: 2009-03-01

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