Acid-catalyzed cyclization of epoxyallylsilanes. An unusual rearrangement cyclization process.
[reaction: see text]. A new route for the synthesis of epoxyallylsilanes bearing the phenyldimethylsilyl group is reported that involves silylcupration of allene, conjugate addition to enones, and sulfur-ylide-mediated epoxidation. The Lewis acid-catalyzed cyclization of these substrates is presented. The expected normal products derived from 5-exo and/or 6-endo attack are not observed; instead, methylenecyclohexanols resulting from a tandem rearrangement-cyclization process are formed.
Departamento de Química Orgánica, Universidad de Valladolid, 47011 Valladolid, Spain.
Asunción
A
Barbero
Pilar
P
Castreño
Francisco J
FJ
Pulido