Unique Reactivity of the 1,4‐Bis(silyloxy)‐1,3‐cyclopentadiene Moiety: Application to the Synthesis of 7‐Norbornanone Derivatives

Abstract

AbstractWe describe a method for the synthesis of various 2‐silyloxy‐2‐norbornen‐7‐ones by exploiting the specific reactivity of the 1,4‐bis(silyloxy)‐1,3‐cyclopentadiene framework, which is generated by the silylation of a 2,2‐disubstituted‐1,3‐cyclopentanedione bearing a picolinoyloxy group at the 2′ position of its C‐2 side chain. The release of the acyloxy group during the reaction generates carbocations that are then attacked by silyloxy‐substituted carbons in the 1,4‐bis(silyloxy)‐1,3‐cyclopentadiene moiety skeleton, forming a 4,5‐cis‐fused ring skeleton. Skeletal rearrangement of the bicyclic core results in the formation of the corresponding 2‐silyloxy‐2‐norbornen‐7‐one. This novel transformation of 1,3‐cyclopentanedione moieties can be used to synthesise other cyclopentenone‐fused bicyclic frameworks.