Asymmetric synthesis of highly functionalized tetracyclic indole bases embodying the basic skeleton of yohimbine-and reserpine type alkaloids

Article abstract of DOI:10.1016/0040-4039(96)00388-7

Schiff bases derived from tryptophan methyl ester react with differently substituted electron-rich siloxy dienes in the presence of achiral or chiral boric acid esters to give enaminones 5 and 6 with high diastereomer ratios (up to >98:2). These intermedi