Nickel‐Catalyzed Asymmetric Hydrogenation of α‐Substituted Vinylphosphonates and Diarylvinylphosphine Oxides

Abstract

Chiral α‐substituted ethylphosphonate and ethylphosphine oxide compounds are widely used in drugs, pesticides, and ligands. However, their catalytic asymmetric synthesis is still rare. Of the only asymmetric hydrogenation methods available at present, all cases use rare metal catalysts. Herein, we report an efficient earth‐abundant transition‐metal nickel catalyzed asymmetric hydrogenation affording the corresponding chiral ethylphosphine products with up to 99 % yield, 96 % ee (enantiomeric excess) (99 % ee, after recrystallization) and 1000 S/C (substrate/catalyst); this is also the first study on the asymmetric hydrogenation of terminal olefins using a nickel catalyst under a hydrogen atmosphere. The catalytic mechanism was investigated via deuterium‐labelling experiments and calculations which indicate that the two added hydrogen atoms of the products come from hydrogen gas. Additionally, it is believed that the reaction involves a NiII rather than Ni0 cyclic process based on the weak attractive interactions between the Ni catalyst and terminal olefin substrate.

The role of attractive dispersion interaction in promoting the catalytic activity of asymmetric hydrogenation

“…7A). 16 The hydrogenation reactivity was high even with aryl-substituted ligands. However, the enantioselectivity of the reaction showed it was sensitive to the alkyl group of the phosphate (R group in Fig.…”

“…Chem., describing their discoveries. [10][11][12][13][14][15][16] In these studies, weak attractive interactions have been found to play an important role by stabilizing the favorable key transition state structure formed by chiral catalysts and substrates and promoting the hydrogenation reaction. These weak attractive interactions could be found as CH⋯HC, CH⋯π, CH⋯O, and other interactions in Zhang and his coworkers' work.…”

Photoactivation‐Induced Emission Enhancement in Benzosilole‐Based Fluorescent Conjugated Microporous Polymer Microspheres with Converse‐Photobleaching Behavior

“…The SF-D4 after photoirradiation manifested a new signal at 10.3 ppm assignable to oxidation products of phosphonium salt, which were further corroborated by 31 P NMR and HRMS spectra (Figures S76 and S77, Supporting Information). [43] In other words, the photoirradiation-inducing complex photoreactions could act as one of the pathways to passivate and renovate the functional group defects, rendering the CMPs a converse-photobleaching behavior. [44] At last, in consideration of the tremendous disparities between defect model molecules and the CMPs, the first principal calculations were performed on 10 high-molecular-weight fragments, named SF-CMP D1 -SF-CMP D10 , which consist of various defects.…”

“…The SF‐D4 after photoirradiation manifested a new signal at 10.3 ppm assignable to oxidation products of phosphonium salt, which were further corroborated by 31 P NMR and HRMS spectra (Figures S76 and S77, Supporting Information). [ 43 ] In other words, the photoirradiation‐inducing complex photoreactions could act as one of the pathways to passivate and renovate the functional group defects, rendering the CMPs a converse‐photobleaching behavior. [ 44 ]…”

The Proton of Alcohols as Hydrogen Source in Diboron-Mediated Nickel-Catalyzed Asymmetric Transfer Hydrogenation of Cyclic N-Sulfonyl Imines

“…In comparison with the well-exploited noble transition-metal-catalyzed asymmetric reduction, earth-abundant transition-metals such as manganese, iron, cobalt, copper, and nickel have recently attracted considerable attention in asymmetric reduction attributing to their relative abundance and lower cost . Particularly, nickel-catalyzed asymmetric reduction has been extensively explored and a series of hydrogen sources have been developed (Scheme a). − ,− In 2008, Hamada and co-workers identified nickel-catalyzed asymmetric hydrogenation of α-amino-β-keto ester hydrochlorides using hydrogen gas as the hydrogen source . Since this pioneering work, impressive progress has been achieved in nickel-catalyzed asymmetric hydrogenation of enamides, alkenes, ketones, imines and oximes with hydrogen gas by Chirik, Zhang, Zhang, Deng, Huang, and our group .…”