A New Strategy for the Enantioselective Synthesis of Carba-Prostacyclin Analogues Based on Organocopper Conjugate Addition to a Bicyclic Azoene and Its Application to the Synthesis of 13,14-Dinor-<i>inter</i>-<i>p</i>-phenylene Carbacyclin
作者:Marc van Bergen、Hans-Joachim Gais
DOI:10.1021/ja0125772
日期:2002.4.1
An enantioselective synthesis of E/Z-13,14-dinor-inter-p-phenylene carbacyclin (E/Z-2d) by a new strategy has been realized that holds the prospect of serving as a general route for carba-prostacyclin analogues. The key intermediate in this synthesis is the bicyclic azoene Ts-9, and the key step is the regio- and stereoselective conjugate addition of the chiral arylcopper compound Cu-8d/P-n-Bu3 to
E/Z-13,14-dinor-inter-p-phenylene carbacyclin (E/Z-2d) 的对映选择性合成已经实现,有望作为卡巴前列环素类似物的一般路线。该合成中的关键中间体是双环偶氮烯 Ts-9,关键步骤是手性芳基铜化合物 Cu-8d/Pn-Bu3 与偶氮烯的区域和立体选择性共轭加成,形成腙7d。从酮 4 对映选择性合成 95% ee 的偶氮烯 Ts-9 分别分四步和五步完成。因此,双环酮 4 与手性碱 Li-10 的对映选择性去质子化和用 ClSiMe3 捕获烯醇锂 11 得到烯醇醚 12,将其用 N-氯琥珀酰亚胺 (NCS) 氯化得到氯酮 13。或者,氯酮 13 也在 11 用 NCS 氯化后制备。氯酮 13 转化为氯腙 14,在用弱碱处理后提供偶氮 Ts-9。98% ee 的芳基铜化合物 8d 由醇 16 分两步获得,醇 16 是通过用 (-)-二异松蒎基氯硼烷对映选择性还原酮