An unexpected benzylic oxidation in the multicomponent synthesis of simplified analogs of anchinopeptolides and eusynstyelamides

The combination of a photoinduced multicomponemt reaction with dimerization of the resulting intermediate can generate complex heterocyclic compounds in a stereodefined manner, with six new bonds and two quaternary carbons formed in just two steps. Remarkably, final heterocycles share the same core with two families of natural products, namely anchinopeptolides and eusynstyelamides. During the synthesis of simplified analogs of these compounds, we came across an unexpected oxidation and decided to study this process, trying to understand the factors able to influence it. We report here preliminary results showing that the structure of the substrates is a key factor in determining the oxidative or nonoxidative outcome of the dimerization reaction.