[reaction: see text] The sesquiterpene (+/-)-herbertenolide was synthesized in seven steps from commercial 2-bromo-4-methylanisole. In the key step, two adjacent stereogenic quaternary centers were controlled by a highly chemoselective and stereospecific photodecarbonylation reaction of crystalline methyl-trans-3-(2-methyl-5-methoxyphenyl)-1,3-dimethyl-2-oxocyclohexancarboxylate (3). An efficient generation
[反应:见正文]
倍半萜烯(+/-)-
香叶烯内酯是由商业上的2-
溴-4-甲基
茴香醚分七个步骤合成的。在关键步骤中,两个相邻的立体异构季
铵盐中心受到结晶甲基-反式-3-(2-甲基-5-
甲氧基苯基)-1,3-二甲基-2-氧代
环己羧酸酯的高度
化学选择性和立体特异性光脱羰反应的控制(3) 。有效生成自由基对和固态施加的立体
化学控制表明该反应可能成为有用的合成方法。