Matoba Hiroaki, Watanabe Takahiro, Nagatomo Masanori, Inoue Masayuki
Graduate School of Pharmaceutical Science , The University of Tokyo , Hongo, Bunkyo-ku, Tokyo 113-0033 , Japan.
Org Lett. 2018 Dec 7;20(23):7554-7557. doi: 10.1021/acs.orglett.8b03302. Epub 2018 Nov 19.
The highly oxygenated 6/8/6-membered ABC-ring 2 of taxol was assembled in a convergent fashion. A decarbonylative radical reaction between α-alkoxyacyl telluride 4 and cyanocyclohexenone 5 linked the A- and C-rings and stereoselectively installed the C2- and C3-tertiary carbon centers of 3. After the C8-quaternary stereocenter was constructed, the C9-methyl ketone and the C11-vinyl triflate of 30 participated in Pd(0)-promoted cyclization of the eight-membered B-ring, giving rise to the taxol skeleton 2.
紫杉醇高度氧化的6/8/6元ABC环2是以汇聚方式组装的。α-烷氧基酰基碲化物4与氰基环己烯酮5之间的脱羰基自由基反应连接了A环和C环，并立体选择性地构建了3的C2和C3叔碳中心。在构建C8季碳立体中心后，30的C9-甲基酮和C11-乙烯基三氟甲磺酸酯参与了钯(0)促进的八元B环环化反应，生成了紫杉醇骨架2。
