Tetrahedron letters

Diastereoselective 5-exo-trig radical cyclisation on N-acryloyl-tetrahydro-1, 3-oxazines. A novel approach to enantiopure 3-substituted pyrrolidines

…, JP Duque-Soladana, JM Iglesias, R Pedrosa

Index: Andres, Celia; Duque-Soladana, J. Pablo; Iglesias, Jesus M.; Pedrosa, Rafael Tetrahedron Letters, 1996 , vol. 37, # 50 p. 9085 - 9086

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Citation Number: 15

Abstract

N-Acryloyl-2-(phenylselenomethyl)-tetrahydro-1, 3-oxazine 1 generates a carbon-centred radical in the presence of tri-n-butyltin hydride and A1BN. This radical underwent diastereoselective 5-exo-trig cyclisation leading to a mixture of five-membered lactams 2a and 2b (de 68%). Chromatographic separation of the diastereomers and elimination of the chiral auxiliary provided enantiopure (R)-3-methylpyrrolidine in good chemical yield.