New [3 + 4] Annulation. Reactions of (β-(Trimethylsilyl)acryloyl)siIanes with the Lithium Enolates of α,β-Unsaturated Methyl Ketones

摘要

We have developed a new [3 + 4] annulation, which involves the reaction of (E)-(β-(trimethylsilyl)acryloyl)-silane 1 with the lithium enolate of α,β-unsaturated methyl ketones and provides an easy access to cis-6-alkyl- and 6,7-cyclo-5-(trimethylsilyl)-2-(silyloxy)-3-cycloheptenones (3). Efforts toward further manipulation of the functionalities of 3 to expand the scope of the [3 + 4] annulation methodology are in progress in this laboratory.