Christopher John Pearson

Asymmetric intramolecular Diels-Alder reactions of sulfoximine-activated trienes

Abstract A series of N-substituted sulfoximidoyl-1,6,8-nonatrienes and 1,7,9-decatrienes were synthesised and subjected to thermal intramolecular Diels-Alder (IMDA) reactions to give diastereomeric mixtures of substituted bicyclo[4.3.0]nonanes and -[4.4.0]decanes. The reactions showed varying selectivities. Endo/exo selectivity was interpreted in terms of a combination of steric factors and the asynchronous nature of the cycloadditions. Diastereofacial selectivity could be rationalised by considering attack by the diene on the less hindered face of the conformationally extended vinylic sulfoximine dienophile.