Premium
Stereoselective Inter‐ and Intramolecular Pauson–Khand Reactions of N ‐(2‐Alkynoyl) Derivatives of Chiral Oxazolidin‐2‐ones
Author(s) -
Fonquerna Sílvia,
Rios Ramon,
Moyano Albert,
Pericàs Miquel A.,
Riera Antoni
Publication year - 1999
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/(sici)1099-0690(199912)1999:12<3459::aid-ejoc3459>3.0.co;2-l
Subject(s) - chemistry , pauson–khand reaction , stereoselectivity , intramolecular force , stereochemistry , organic chemistry , combinatorial chemistry , catalysis
A complete account of the intermolecular and intramolecular Pauson–Khand reactions of N ‐(2‐alkynoyl) derivatives of chiral 2‐oxazolidinones is presented. The intermolecular Pauson–Khand reactions with norbornene or norbornadiene take place under mild conditions and in high yields. Phenyl‐ or trimethylsilylpropiolate derivatives lead to the exclusive formation of 1,4‐dicarbonyl regioisomers, while mixtures of 1,3‐ and 1,4‐regioisomers are obtained with tetrolate derivatives. The diastereoselectivity of the reaction, determined by the substitution pattern of the oxazolidinone moieties, can be very high (up to 17.5:1 dr ) for the formation of 1,4‐dicarbonyl regioisomers, and the diastereomeric products can often be separated by column chromatography. Under the appropriate conditions, the intramolecular Pauson–Khand reactions of oxazolidinone‐derived enynes can also take place with very good yields, but with low diastereoselectivities. The absolute configurations of several adducts have been determined, and the stereochemical outcome of the reaction has been rationalized.