Electrocyclization of Arylvinyl Oxetane/1,3-Diol to Substituted Indenyl Acetaldehyde via Indene–Ethanol, Oxepine, and a 1,6-Hydride Shift

We intended to realize aryl vinyl oxetane as a 4π-electrocyclization precursor to access indene ethanol. Interestingly, we found that the readily accessible aryl vinyl 1,3-diol, an intermediate en route to the synthesis of oxetane, is an equally potential precursor for the anticipated cyclization. Moreover, aryl vinyl 1,3-diol/oxetane and indene ethanol readily reacted with the subsequently added (het)aromatic aldehydes, providing various indene oxepines/acetaldehydes. Additionally, indenyl aldehyde served as a synthetic handle for FGI, further expanding this protocol's scope.