1339751-88-0Relevant academic research and scientific papers
Stereoselective preparation of β-aryl-β-boronyl enoates and their copper-catalyzed enantioselective conjugate reduction
Ding, Jinyue,Lee, Jack Chang Hung,Hall, Dennis G.
supporting information, p. 4462 - 4465 (2012/10/30)
A new methodology has been developed for the stereoselective preparation of β-aryl-β-boronyl α,β-unsaturated esters via Heck coupling, and their subsequent copper(I)-catalyzed enantioselective conjugate reduction. Various chiral secondary boronate derivatives can be accessed in excellent yields and good to high levels of enantioselectivity through the efficient copper-catalyzed process using polymethylhydrosiloxane (PMHS) as the hydride source.
Enantioselective preparation and chemoselective cross-coupling of 1,1-diboron compounds
Lee, Jack Chang Hung,McDonald, Robert,Hall, Dennis G.
experimental part, p. 894 - 899 (2012/07/27)
The simplicity, efficiency and generality of the transition-metal-catalysed Suzuki-Miyaura cross-coupling reaction has led to its application in the preparation of a wide variety of organic compounds. Cross-coupling of alkylboron derivatives, however, remains a major challenge, in particular with regard to stereochemical control. Here, we describe the preparation and reaction of highly optically enriched 1,1-diboron compounds. A catalytic asymmetric conjugate borylation of β 2-boronylacrylates provided geminal diboronate products that feature two distinct boronyl units, in 99% enantiomeric excess. Chemoselective cross-coupling of one-boronyl unit, a trifluoroborate salt, occurred stereospecifically via inversion of its configuration to generate enantioenriched benzylic or allylic boronates. The difficult transmetallation in the Suzuki-Miyaura catalytic reaction cycle is believed to be facilitated by a stabilization effect from the second boronyl unit, and internal coordination by the oxygen of the proximal carboxyester. We also explored subsequent functionalization of the second boronyl unit.
