三环二酮醇5(3-苯硫基-6,9,10-三甲基-12-羟基三环[7.4.0.02~6]trideca-2,1O-diene-4,8-dione),可能是cyathins合成的中间体,已从 2,5-二甲基-对-苯醌开始制备。5 的结构和立体化学通过相应对溴苯甲酸酯 (6) 的 X 射线晶体学研究得到证实。尝试将 5 中的顺式 BC 环连接异构化以得到相应的反式化合物,但未成功。从5中除去噻吩基团得到化合物180,其在碱催化异构化作用下提供顺式和反式化合物的平衡混合物。WILLIAM A. AYER、DALE E. Ward、LOIS M. BROWNE、LOUIS TJ DELBAERE 和 YUMIKO HOYANO。能。J.化学。59,2665 (1981)。A partir de la dimethyl-2, 在 etabli la structure et lastereochimie
三环二酮醇5(3-苯硫基-6,9,10-三甲基-12-羟基三环[7.4.0.02~6]trideca-2,1O-diene-4,8-dione),可能是cyathins合成的中间体,已从 2,5-二甲基-对-苯醌开始制备。5 的结构和立体化学通过相应对溴苯甲酸酯 (6) 的 X 射线晶体学研究得到证实。尝试将 5 中的顺式 BC 环连接异构化以得到相应的反式化合物,但未成功。从5中除去噻吩基团得到化合物180,其在碱催化异构化作用下提供顺式和反式化合物的平衡混合物。WILLIAM A. AYER、DALE E. Ward、LOIS M. BROWNE、LOUIS TJ DELBAERE 和 YUMIKO HOYANO。能。J.化学。59,2665 (1981)。A partir de la dimethyl-2, 在 etabli la structure et lastereochimie
Enantioselective Total Synthesis of Cyathin A<sub>3</sub>
作者:Dale E. Ward、Jianheng Shen
DOI:10.1021/ol070994z
日期:2007.7.1
The total synthesis of (-)-cyathin A3 is described. The keystep involves an unusual enantioselective Diels-Alderreaction of 2,5-dimethyl-1,4-benzoquinone with 2,4-bis(trimethylsilyloxy)-1,3-pentadiene, using Mikami's catalyst [(R)-BINOL + Cl2Ti(OiPr)2 + 4 A mol sieves] modified by addition of Mg and SiO2. Because cyathin A3 is easily transformed into allocyathin B3, cyathin B3, cyathin C3, and neoallocyathin
Synthetic studies on cyathin diterpenes - Total synthesis of (±)-allocyathin B<sub>3</sub>
作者:Dale E Ward、Yuanzhu Gai、Qi Qiao、Jianheng Shen
DOI:10.1139/v03-185
日期:2004.2.1
The synthesis of racemic allocyathin B3 from an advanced intermediate possessing the ring system and relative stereochemistry but lacking the isopropyl and hydroxymethyl groups is reported. The isopropyl group was introduced by radical cyclization of a methyl propargyl acetal of an α-bromoketone and the hydroxymethyl group was generated by Pd-catalyzed carbonylation of a vinyl triflate. The route provides