Visible-Light-Induced Tandem Radical Addition–Cyclization of Alkenyl Aldehydes Leading to Indanones and Related Compounds
作者:Danyang Lu、Yimei Wan、Lichun Kong、Gangguo Zhu
DOI:10.1021/acs.orglett.7b01162
日期:2017.6.2
Herein we describe a novel, visible light-induced tandemradicaladdition–cyclization of alkenyl aldehydes with α-bromocarbonyl compounds. A set of cyclic ketones, including indanones, cyclopentenones, 3,4-dihydronaphthalen-1(2H)-ones, and chroman-4-ones, are synthesized at room temperature with high efficiency and good functional group compatibility. It represents the first report on the catalytic
An optically active vinylic sulfoxide bearing a leaving group at the γ-position was stereoselectively transformed into a chiral cyclopropane by means of a Michael addition with an allylmagnesium bromide. The Michael induced ring-closure reaction requires both allylmagnesium bromide as a uncleophile and chloride as a leaving group for high diastereoselectivity. The absolute stereochemistry of the cycloadduct was confirmed by X-ray analysis.
通过与烯丙基溴化镁的迈克尔加成反应,一种在 γ 位带有离去基团的光学活性乙烯基亚砜被立体选择性地转化为手性环丙烷。迈克尔诱导的闭环反应需要溴化烯丙基镁作为不亲和基和氯化物作为离去基团才能实现高非对映选择性。通过 X 射线分析确认了环加合物的绝对立体化学性质。
Highly enantioselective construction of a quaternary carbon centre by the Pummerer-type reaction: a total synthesis of (–)-sibirine
Highly enantioselective quaternary carbon formation (96% enantiomeric excess) is achieved by the Pummerer-typereaction of a chiral vinylic sulphoxide with allylmagnesium bromide; this method is applied to the synthesis of (–)-sibirine.
An efficient method for the construction of dihydroquinoline derivatives possessing a quaternary carbon center is developed by an application of Hg(OTf)(2)-catalyzed vinylogous semi-pinacol-type rearrangement. The reaction was found to be specifically catalyzed by mercury salt and to proceed via a bicyclic aminal.