[2,3] Sigmatropic rearrangement of 1-vinylic tetrahydroisoquinoline N-ylides and N-oxides.

Abstract

[2.31 Sigmatropic rearrangement of the N-ylides from the 1-vinyl and 1-(1-propenyl) tetrahydroisoquinolinium salts 3a and 3b at room temperature in acetonitrile gave high yields of the functionalised 3-benzazonine derivatives 6a (90%: E/Z = 19) and 6b (93%: E/Z = 2) respectively. The N-oxide analogues 4a and 4b gave the 2,3-benzoxazepines 8a and 8b. together with the first representative of the 4,3-benzoxazonine system, 9b, from 4b. Show more