Metal-Free Oxidative Ipso-Carboacylation of Alkynes: Synthesis of 3-Acylspiro[4,5]trienones from N-Arylpropiolamides and Aldehydes

A general and metal-free radical route to synthesis of 3-acylspiro[4,5]trienones is established that utilizes TBHP (tert-butyl hydrogenperwdde) as an oxidation and a reaction partner to trigger the oxidative ipso-carboacylation of N-arylpropiolamides with aldehydes. This method offers a new difunctionalization of alkynes through oxidative cross coupling of the aldehyde C(sp(2))-H bond with an ipso-aromatic carbon.