A concise synthesis of (E)-3-aryl-2,3,4,5-tetrahydro-1H-3-benzazonines by aryne induced [2,3] Stevens rearrangement of 1,2,3,4-tetrahydroisoquinolines

A mild and transition-metal-free approach for the synthesis of (E)-3-aryl-2,3,4,5-tetrahydro-1H-3-benzazonines via [2,3] Stevens rearrangement of 1,2,3,4-tetrahydroisoquinolines with arynes is described. This protocol provides straightforward access to (E)-3-aryl-2,3,4,5-tetrahydro-1H-3-benzazonines in moderate to good yields with excellent diastereoselectivity. A broad range of functional groups, involving nitrile, esters, ketone and aryl halide, were well tolerated in this reaction.