Lithiation of 2-Aryl-2-(chloroaryl)-1,3-dioxolanes and Its Application in the Synthesis of Newortho-Functionalized Benzophenone Derivatives
作者:Gyula Lukács、Márta Porcs-Makkay、Gyula Simig
DOI:10.1002/ejoc.200400335
日期:2004.10
2-Aryl-2-(chloroaryl)-1,3-dioxolanes 4 were lithiated ortho to the ketal group of the chloroaryl ring by treatment with butyllithium in THF between −78 and 0 °C. The site selectivity of some of the deprotonation reactions was rationalized by the long-range effect of the 4-chloro substituent. The lithio species thus generated were treated with various electrophiles to give ortho-functionalized benzophenone
2-芳基-2-(氯芳基)-1,3-二氧戊环 4 通过在-78 和 0 °C 之间的 THF 中用丁基锂处理,在氯芳基环的缩酮基团的邻位锂化。一些去质子化反应的位点选择性通过 4-氯取代基的长程效应合理化。用各种亲电试剂处理由此产生的锂硫物质,得到邻位官能化的二苯甲酮衍生物。在 2-(4-氯苯基)-2-(4-氟苯基)-1,3-二氧戊环 (4s) 的锂化过程中观察到芳环之间的分子内竞争。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)