Base-mediated hydrolytic cleavage with chain migration of 1-chloromethyl-tetrahydropyrano[3,4-b]indoles: an unusual pathway to 2-succinoyl tryptophols

An unusual hydrolytic cleavage with 1,2-alkyl chain migration of 1-chloromethyl-tetrahydropyrano[3,4-b]indoles by heating with a limited amount of water and base in DMF is reported. A mechanism for the formation of 1,2-alkyl chain migration products, 2-succinoyl tryptophols, and the ring-expansion products, dihydro-oxepine fused indoles, is reported. No comparable 1,2-chain migration from a structurally related 1-chloromethyl-isochroman is observed.