Oxo-Sulfonylation of 1,7-Enynes via a Multicomponent Oxidative Radical Polar Crossover Approach

Diastereoselective synthesis of trans-3,4-difunctionalized tetrahydroquinoline and chromane derivatives via the oxo-sulfonylation of 1,7-enynes is demonstrated. The reaction involves a three-component oxidative radical polar crossover (ORPC) approach wherein a vinyl carbocation intermediate undergoes nucleophilic substitution to afford the corresponding keto functional group. Deprotection of the N-Ts group, gram-scale synthesis, and other synthetic applications were illustrated. Control experiments and mechanistic studies show that water acts as the nucleophile in this reaction.