Studies on the synthesis of Strychnos indole alkaloids

Article abstract of DOI:10.1016/S0040-4020(01)87138-6

Tetracycles 3b-d, having the ABCD ring substructure of Strychnos alkaloids and a N(b)-(formylmethyl) substituent protected as an oxime or hydrazone derivative, have been prepared by nucleophilic addition of the enolate of indoleacetic ester 1 to pyridinium salts 2b-d followed by acid cyclization. The same one-pot, two-step sequence allowed the preparation of tetracycle 3f, which incorporates an α-methoxyacrylate chain at the piperidine β-position.