Synthetic studies with 7-functionalised norbornenes, and their synthesis by a silicon-controlled carbocation rearrangement
作者:Ian Fleming、Joseph P. Michael
DOI:10.1039/p19810001549
日期:——
7-functionalised norbornenes. Thus the epoxide (13) of methyl 7-anti-trimethylsily bicyclo[2.2.1]hept-5-ene-2-endo-carboxylate (12) rearranges on treatment with boron trifluoride–ether to give methyl 7-anti-hydroxybicylo[2.2.1]hept-5-ene-2-exo-carboxylate (14), and treatment of (12) with bromine gives mainly the rearranged bromide, methyl 7-anti-bromobicyclo[2.2.1]hept-5-ene-2-exo-carboxylate (16)
作为葡糖胺(1)的预期合成的一部分,描述了7-氧代双环[2.2.1]庚-5-烯-2-内,3-外-二羧酸二甲酯(5)的合成。该路线涉及由银离子在甲醇中催化的5- exo -bromo -3- exo-甲氧羰基-7-抗-三甲基硅双环[2.2.1]庚烷-2,6-carbactactone(9)的硅控制重排。给予二甲7-顺-hydroxybicyclo [2.2.1]庚-5-烯-2-内型,3-外型-d icarboxylate(11)。一些相关反应表明,降冰片烯中的7-三甲基甲硅烷基可用于合成其他7-官能化的降冰片烯。因此,甲基7-抗氧化剂的环氧化物(13)-三甲基双环[2.2.1]庚-5-烯-2-内羧酸盐(12)在三氟化硼-醚处理中重排,得到甲基7-抗羟基双[2.2.1]庚-5-烯-2 -外羧酸盐(14),和用溴处理(12),主要得到重排的溴化物,甲基-7-抗-溴双环[2.2.1]庚-5-烯-2