Hypervalent Iodine(III)‐Mediated Oxidative Cyclization of <i>Exo</i>‐Cyclic Ene‐Carbamate to Tetrahydroisoquinoline‐Oxazol‐2(3<i>H</i>)‐one Derivatives

The new development of a transition-metal-free method for the synthesis of THIQ-oxazol-2(3H)-one motif from exo-cyclic ene-carbamates by using hypervalent iodine as an oxidant is reported. Various functional groups substituted on the aryl rings of the ene-carbamate substrates as well as the N- and S-heterocyclic substrates afforded the corresponding THIQ-oxazol-2(3H)-one products in up to 91 % yield. Moreover, the synthetic utility was highlighted for the synthesis of phthalide-THIQ natural product, (±)-corlumine.