Portal de Periódicos da CAPES

α′-Benzoyloxy and α′-methoxymethoxy lithium enolates giving opposite diastereofacial selectivities in aldol reactions. Use of (probable) extended chelation for reversal of stereoselectivities

1993; Elsevier BV; Volume: 34; Issue: 14 Linguagem: Inglês

10.1016/s0040-4039(00)77578-2

1873-3581

Anusuya Choudhury, Edward R. Thornton,

Chemical Reaction Mechanisms

Abstract The Li enolates of α-benzoyloxy and α-methoxymethoxy ketones 1a and 1c afford nonchelation and chelation aldol products, respectively, both with usefully high diastereofacial selectivities. Evidence suggests that transition state chelation of the benzoyl C=O is responsible for the observed “nonchelation” stereoselectivity of 1a .