Recent Developments in Enantioselective Nickel(II)‐Catalyzed Conjugate Additions

Abstract

International audienceDuring the last ten years, an important number of novel highly efficient asymmetric conjugate additions of various nucleophiles to numerous acceptor-activated olefins have been developed on the basis of asymmetric nickel(II) catalysis by the very fact of the lower costs of nickel catalysts in comparison with other transition metals. These processes can be considered as one of the most powerful and reliable tools for the stereocontrolled formation of carbon-carbon bonds. Importantly, a range of fascinating nickel-catalyzed asymmetric domino reactions initiated by Michael additions has been successfully developed. The goal of this review is to collect the major developments in enantioselective nickel-catalyzed conjugate additions reported since the beginning of 2004, well illustrating the power of these inexpensive and highly abundant catalysts to achieve functionalized chiral compounds to be applied as key intermediates in the synthesis of biologically interesting molecules including natural products

Naked d-orbital in a centrochiral Ni(II) complex as a catalyst for asymmetric [3+2] cycloaddition

“…Over recent decades, the use of asymmetric nickel catalysts has substantially evolved both in acid–base and redox catalysis456. Several examples of chiral nickel complexes that act as asymmetric catalysts have been sporadically characterized by X-ray structure analysis, opening up a window of opportunity to discuss the stereo-discrimination process in asymmetric nickel catalysis7891011121314151617.…”

Enantioselective Conjugate Addition of 2‐Acylimidazoles with Nitroalkenes Promoted by Chiral‐at‐Metal Rhodium(III) Complexes

“…Nitroalkanes are highly versatile synthetic intermediates on account of their facile α ‐alkylation reactions and interconversions to other important functional groups by various possible transformations . Therefore, catalytic diastereo‐ and enantioselective conjugate additions of carbon pronucleophiles to nitroalkenes has attracted much attention . The substrate‐controlled enantioselective Michael additions of ketones to nitroalkenes have been intensively investigated before the emergence of organocatalysts .…”

“…However, this catalytic system is limited by a relatively large catalyst loading (usually 10–20 mol%) and a long reaction time. Complementarily, organometal complexes have been recognized as attractive catalysts and received continuous and ever‐growing attention in this research area during the last decade . The combination of chiral diamine ligands with a metal such as Ni, Ca, Cu and Mn has been well investigated in asymmetric conjugate addition with nitroalkenes.…”

Renovation of Optically Active Phenanthrolines as Powerful Chiral Ligands for Versatile Asymmetric Metal Catalysis

“…Disappointingly, the reaction of 14a with the Cu(II) complex of ( S )‐ 1a gave the product 18a in a low yield and the racemic form. The subsequent screening of metal precursors revealed that only the reaction with the complex of nickel(II) acetate tetrahydrate and (S)‐ 1a gave ( R )‐ 18a in quantitative yield and with moderate enantioselectivity 28. To further increase the ee value, we introduced an additional effective chiral environment within ( S )‐ 1a .…”