Synthesis of α,α′-<i>trans</i>-Oxepanes through an Organocatalytic Oxa-conjugate Addition Reaction

Abstract

Oxepanes are found in a wide range of natural products; however, they are challenging synthetic targets due to enthalpic and entropic barriers. Organocatalytic oxa-conjugate addition reactions promoted by the <i>gem</i>-disubstituent (Thorpe–Ingold) effect stereoselectively provided α,α′-<i>trans</i>-oxepanes. In addition, the potential of an organocatalytic tandem oxa-conjugate addition/α-oxidation was demonstrated in a rapid generation of molecular complexity. These organocatalytic oxa-conjugate addition reactions would provide powerful tools for the synthesis of natural products that contain highly functionalized oxepanes