Reaction of quinidine acetate, epiquinidine and its acetate in superacid: formation of gem-difluoro derivatives with or without rearrangement
作者:Sébastien Debarge、Bruno Violeau、Marie-Paule Jouannetaud、Jean-Claude Jacquesy、Alain Cousson
DOI:10.1016/j.tet.2005.10.004
日期:2006.1
presence of CCl4. Under similar conditions quinidine acetate 1b and epiquinidine acetate 2b dihydrochlorides both yield 10,10-difluoro derivatives epimeric at C-3, 6 and 7, and 9c and 10b, and a rearranged difluoro derivative 8b and 11b, respectively. Epiquinidine 2a leads to the expected analogues 10a and 11a and to a ketone 9a. Formation of gem-difluoro compounds implies chloro intermediates at C-10
在HF-SbF 5中,奎尼丁1a或它的二盐酸盐环化物以前是用通常的酸获得的。在CCl 4的存在下观察到类似的反应。在类似条件下奎尼丁醋酸1B和epiquinidine醋酸2b的二盐酸盐产率二者10,10-二氟衍生物差向异构体在C-3,6和7,以及图9C和图10B,以及重排的二氟衍生物8B和11B分别。表奎尼丁2a生成预期的类似物10a和11a并生成酮9a。宝石-二氟化合物的形成意味着C-10处的氯中间体,即α-氯碳鎓离子的前体,它们被氟离子捕获,并通过卤素交换引入产物中。