The quasi-homo-anomeric interaction in substituted tetrahydropyranyl radicals: Diastereoselectivity

摘要

The isomer distribution of products from the reaction of a range of simple cyclohexyl and tetrahydropyranyl radicals (3 -7) with Bu3SnD and with allyltributyltin, has been determined in order to gauge the influence of the classical anomeric effect and the quasi-homo-anomeric effect on stereoselectivity. In these unencumbered radicals, both anomeric effects caused a strong preference for bans deuterated products, but no significant stereoselectivity was observed for the allylation reactions. The difference between the two types of reaction suggests that deuteration is mainly under kinetic control whereas allylation has a greater tendency for thermodynamic control. (C) 1998 Elsevier Science Ltd. All rights reserved. [References: 21]