Ring A building blocks for taxoids and taxamycins

Abstract

The syntheses of a series of oxygenated cyclohexene ring A synthohs 20, 22–27, 34, 36, and 37 that possess suitable functionality for further elaboration for taxoid synthesis are described. These compounds have been prepared from β-ionone by a series of oxidative and addition reactions or alternatively by Lewis acid catalyzed Diels–Alder cycloadditions with the oxygen-containing trimethyl substituted dienes 31 and 33. Keywords: taxoid, paclitaxel, dienes, Diels–Alder, β-ionone.