Preparation and Addition−Elimination Reactions of Benzyl α,β,β-Trifluoroacrylate. A New Stereoselective Approach to (<i>Z</i>)-β-Substituted α,β-Difluoroacrylates
作者:Shigeyuki Yamada、Mayumi Noma、Kazunori Hondo、Tsutomu Konno、Takashi Ishihara
DOI:10.1021/jo701975y
日期:2008.1.1
Benzyl α,β,β-trifluoroacrylate (1) was prepared in good yield via the reductive Br−F elimination of benzyl 2-bromo-2,3,3,3-tetrafluoropropanoate or the palladium-catalyzed cross-coupling reaction of 1,2,2-trifluorovinylstannane with benzyl chloroformate. On treating 1 with various Grignard reagents or dialkylzinc reagents in the presence of copper(I) salt, the corresponding β-substituted α,β-difluoroacrylates
通过还原性Br-F消除2-溴-2,3,3,3,3-四氟丙酸苄酯或钯催化的1,的交叉偶联反应,高收率制备了α,β,β-三氟丙烯酸苄酯(1)。 2,2-三氟乙烯基锡烷与氯甲酸苄酯。在铜(I)盐存在下用各种格氏试剂或二烷基锌试剂处理1,可以以高收率和高Z-选择性获得相应的β-取代的α,β-二氟丙烯酸酯。此外,三烷基铝试剂也被认为是良好的亲核试剂,相应的加成消除产物的收率高,但立体选择性低。