Synthetic Studies on Polyquinane Sesquiterpenes

多醌骨架是许多天然有机化合物的重要结构单元，其中一些化合物具有重要的生物活性。本课题以1为中间体，通过环丙烷环上的C_2-C_8键的区域选择性断裂，成功地合成了两个聚喹烷型倍半萜化合物，其中1的Birch还原反应通过环丙烷环上的C_2-C_8键断裂，只得到双环3.3.0辛烷2，而1在亲核取代条件下经C_1-C_2二次裂解主要生成双环3.2.1辛烷3。另一方面，从1容易得到的羧酸4通过分子内羧酸参与的唯一C_1-C_2键断裂有效地得到内酯5。完成了具有代表性的三醌型倍半萜并环戊二烯（6）、去羧基四酮（7）和抗肿瘤的二醌型倍半萜四酮（9）的全合成还分别利用关键中间体3和8合成了2-（2-甲氧基苯基）-3-（2-甲氧基苯基）-2-（2-甲氧基苯基）-3-（2-甲氧基苯基）-4-（2-

Polyquinane framework plays an important role of structural unit of many kinds of naturally occurring organic compounds, some of which exhibit significantly biological activities. In this project, a couple of poluquinane sesquiterpenes were successfully synthesized by the use of a common intermediate 1 which was subjected to regioselective C-C bond cleavage of cyclopropane ring.The Birch reduction of 1 exclusively afforded the bicyclo 3.3.0 octane 2 via C_2-C_8 bond fission of the cyclopropane ring, while treatment of 1 under nucleophilic substitution conditions gave the bicyclo 3.2.1 octane 3 as a main product via the C_1-C_2 ond cleavage. On the other hand, the carboxylic acid 4, easily obtained from 1, afforded the lactone 5 efficiently through the exclusive C_1-C_2 bond fission by an intramolecular carboxylic acid participation.Through the several-step sequence starting from 2, total synthesis of a representative triqyinane sesquiterpene pentalenene (6) was accomplished.Descarboxyquadrone (7) and an antitumor diquinane sesquiterpene quardrone (9) were also synthesized by the use of key intermediates 3 and 8,respectively.