A weakly coordinating aldehyde as a traceless directing group for rhodium-catalyzed regioselective C–H alkenylation of benzaldehydes

Abstract

A rhodium-catalyzed regioselective C–H alkenylation of benzaldehydes has been developed employing acrylates as alkenyl surrogates, in which a weakly coordinating aldehyde is rarely utilized as a traceless-directing group. This approach offers direct access to less common meta-alkenylated aromatic compounds starting from more accessible ortho- or para-substituted benzaldehydes. The natural product 3aa was successfully synthesized in a single step using this protocol demonstrating its synthetic utility. Notably, the active catalyst is regenerated via two plausible pathways involving metal oxidation and hydrogen transfer with acrylates serving as efficient hydrogen scavengers.