was transformed into (+)-5 and (+)-1. A stepwise stereoselective synthesis of (+)-1 was also developed utilizing an oxyselenylation ring-closure reaction. The synthetic sequence also produced four biologically active naturally occurring drimanic sesquiterpenes, (+)-drimane-8α,11-diol (34), (−)-drimenol (38), (+)-albicanol (39), and (−)-albicanal (31) as intermediates.
四环
吡喃(+)-
氯普苯酮(1)和(+-
氯普
苯酚(5)及其C8- R-异构体(+)- 3)是通过1-
氯-2-
硫代-3的一锅缩合反应合成的, 5,6-三(叔丁基二甲基甲
硅烷氧基)苯(8)与(4a S,8a S)-
3,4,4a,5,6,7,8,8a-八氢-2,5,5,8a-
四甲基萘-1-
甲醛(7)。主要缩合产物(4a S,6a R,12b S)-2 H -9,10-双(叔丁基二甲基甲
硅烷氧基)-11-
氯-1,
3,4,4a,5,6,6a,12b-八氢-4,4,6a,12b-四甲基-苯并[ a甲
硅烷基(4),经去甲
硅烷基化后提供四环
吡喃(+)-(4a S,6a R,12b S)-2 H -11-chloro-1,
3,4,4a,5,6,6a,12b-八氢-4,4,6a,12b-四甲基-苯并[ a ] x吨-9,10
-二醇(3)。在8小时内以42 mg / rat的剂量使用时,
吡喃二醇3抑制大鼠肠道中胆