Catalytic Enantioselective Synthesis of Highly Functionalized Difluoromethylated Cyclopropanes

Abstract

The first catalytic asymmetric synthesis of highly functionalizeddifluoromethylated cyclopropanes is described. The method, based on arhodium-catalyzed cyclopropanation of difluoromethylated olefins,gives access to abroad range of cyclopropanes bearing ester,ketone,ornitro functional groups. By using Rh 2 ((S)-BTPCP) 4 as ac atalyst, the corresponding products were obtained in high yields and high diastereo-and enantioselectivities (up 20:1 d.r.a nd 99 %e e). This methodology allowed preparation of enantioenriched difluoromethylcyclopropanes for the first time.

Transition‐Metal‐Free Defluorosilylation of Fluoroalkenes with Silylboronates

“…Treatment of compound 10b with benzaldehyde in the presence of TBAF could form a homoallylic alcohol 38 in 74% yield (Scheme b). In addition, the reaction of silylated fluoroalkene 13b with water and TBAF could afford CF 2 H‐substituted counterpart 39 in good yield (Scheme c) . Therefore, this defluorosilylative process can act as a key step in the synthesis of various CF 2 ‐substituted vinyl targets from easily accessible trifluoromethylalkenes.…”

Preise des Chemical Institute of Canada und der Canadian Society for Chemistry

“…Charette und seine Gruppe entwickeln neue Methoden zur stereoselektiven Synthese organischer Verbindungen und Naturstoffe.I nd er Angewandten Chemie berichtete er über die katalytische asymmetrische Synthese hoch funktionalisierter Cyclopropane. [2] Alex Adronov (McMaster University) ist der Gewinner des CIC Macromolecular Science and Engineering Award. Adronov studierte an der McMaster University und promovierte 2001 unter Anleitung von Jean M. J. FrØchet an der University of California, Berkeley.Anschließend kehrte er an die McMaster University zurück, an der er seit 2013 eine Professur innehat.…”