Selectivity in vinyl azide reactions; decomposition of azidocinnamates with olefinic ortho-substituents

Thermal decomposition of vinyl azides (1a–c) gives isoquinolines (3), benzazepines (4), or aziridines (5) and (6) by preferential reaction at the unsaturated substituent; removal of this unsaturation as in the epoxides (1d,1e) leads exclusively to 4-substituted indoles.