A route to a wide range of cyclopentanecarboxylic acids via 4-substituted camphors
作者:Volodymyr O. Knizhnikov、Zoya V. Voitenko、Vladimir B. Golovko、Marian V. Gorichko
DOI:10.1016/j.tet.2011.12.053
日期:2012.2
steps. Regioselective bromination of 4-carboxy- and 4-methoxycarbonyl-3-bromocamphors leads to 10-bromomethyl derivatives in good yields. Grob-type fragmentation reactions proceed smoothly for 10-bromocamphor-4-carboxylic acid, 10-bromocamphorquinone-4-carboxylic acid and 3,4-dibromocamphor with the formation of unsaturated cyclopentanecarboxylic acids. Detailed studies of bromination and rearrangement
4-樟脑樟脑易于从樟脑中获得,仅需几个步骤即可用作多种环戊烷羧酸的高产率合成中的多用途前体。4-羧基和4-甲氧基羰基-3-溴樟脑的区域选择性溴化以良好的收率产生10-溴甲基衍生物。对于10-溴代樟脑-4-羧酸,10-溴代樟脑醌-4-羧酸和3,4-二溴代樟脑,团簇型裂解反应平稳进行,形成不饱和环戊烷羧酸。本文报道的对溴代樟脑-4-羧酸及其衍生物的溴化和重排反应的详细研究突显了取代樟脑的独特化学性质,并易于获得各种2,2-二甲基-3-亚甲基环戊烷羧酸衍生物。