Several MOP ligands 5 containing aryl groups at 2′ position of (R)-2-(diphenylphosphino)-1,1′-binaphthyl skeleton were prepared and used for palladium-catalyzed asymmetric hydrosilylation of cyclic 1,3-dienes 6 with trichlorosilane. Highest enantioselectivity was observed in the reaction of 1,3-cyclopentadiene (6a) catalyzed by a palladiumcomplex (0.25 mol %) coordinated with (R)-2-(diphenylphosphino)-2′-(3
Functionalization of Unactivated Alkenes through Iridium-Catalyzed Borylation of Carbon−Hydrogen Bonds. Mechanism and Synthetic Applications
作者:Vilhelm J. Olsson、Kálmán J. Szabó
DOI:10.1021/jo9014694
日期:2009.10.16
methylimidazole and DBU, the iridium-catalyzed borylation led to formation of allyl boronates, which reacted with aldehydes in a one-pot sequence affording stereodefined homoallylic alcohols. Cycloalkenes without additives as well as acyclic substrates gave vinylic boronates, which were coupled with organohalides in a Suzuki−Miyaura sequence. By this process allylic and vinylic silabutadiene derivatives
Catalytic asymmetric allylation of aldehydes with alkenes through allylic C(sp<sup>3</sup>)–H functionalization mediated by organophotoredox and chiral chromium hybrid catalysis
describe a hybrid system that realizes cooperativity between an organophotoredox acridinium catalyst and a chiral chromium complex catalyst, thereby enabling unprecedented exploitation of unactivated hydrocarbon alkenes as precursors to chiral allylchromium nucleophiles for asymmetricallylation of aldehydes. The reaction proceeds under visible light irradiation at room temperature, affording the corresponding