Rh-catalysed single-carbon insertion to 1,3-dienes

Herein, we report the first catalytic single-carbon insertion to 1,3-dienes with Rh(ii)-carbynoids. The skeletal editing process is based on the catalytic generation of a Rh-carbynoid that promotes the insertion of a cationic monovalent carbon unit (:+C-R) into the C(sp 2 )-C(sp 2 ) bond of the 1,3-diene, leading to a pentadienyl cation. Regioselective attack on the latter species leads to the formation of multi-substituted 1,3-dienes or 1,4-dienes with a broad range of carbon and heteroatomic nucleophiles.