(iPrO)3TiCl-induced reactions of α- and β-4(20)-epoxy-5-hydroxytriacetyltaxicin I
作者:Qian Cheng、Takayuki Oritani、Tohru Horiguchi
DOI:10.1016/s0040-4020(99)00707-3
日期:1999.10
Chlorolitanium triisopropoxide-induced reaction of alpha-4(20)-epoxy-5-hydroxytriacetyltaxicin I 2 gave a 4-hydroxymethylene-5-one 4 and a 4-hydroxy-4-chloromethylene 5, while the corresponding beta-4(20)-epoxide 3 gave a 3,8-cyclopropane 6 and a 6/8/5 ring system 7. Moreover, boron trifluoride-induced reaction of the a-4(20)epoxide 2 yielded a 6/8/6/7 ring system 8 and an A-ring contracted alcohol derivative 9. Plausible mechanisms of these reactions are proposed. (C) 1999 Elsevier Science Ltd. All rights reserved.