Four new taxane diterpenes, 9a-hydroxy-14fl-(2-methylbutyryl)oxy-2a,5a, lOfl-triacetoxytaxa-4(20), 11-diene, 2a,5t~,9ot, 1 Off, 14fl-pentaacetoxytaxa-4(20), 11-diene, 5a-(cinnamoyl)oxy-7fl-hydroxy-9a, 1 Off- 13 a-triacetoxytaxa-4(20),ll-diene and 5ct-hydroxy-9a, lOfl,13ct-triacetoxytaxa-4(20),ll-diene, along with 12 known taxa-4(20),ll-dienes, have been isolated from twigs of Taxus mairei and their structures determined by spectral methods. Copyright © 1996 Elsevier Science Ltd