Recent Advances in Nonprecious Metal Catalysis

Abstract

Nonprecious metal catalysts are cost-effective and sustainable alternatives to other commonly used, expensive transition metals. Therefore, process chemists across various industries have invested in this technology, harnessing iron, cobalt, nickel, copper, as well as other metals to catalyze well-studied and novel transformations. This review continues a series highlighting industry-relevant literature published in the field of nonprecious metal catalysis between November 2020 and February 2021.

Recent Advances in Nonprecious Metal Catalysis

“…The development of novel methods for ligand and precatalyst structures in the area of Ni catalysis continues to attract many research groups to explore Ni precatalysts of high stability and effective applications with novel ligands. Advancement in this field provides attractive alternatives to precious metal catalysis by expanding their application space in a wide range of reactions such as Suzuki couplings, Buchwald−Hartwig couplings, Negishi couplings of both C(sp 2 ) and C(sp 3 ) electrophiles and nucleophiles, C−H functionalizations, and others. Earlier reports in this review series elaborated on the development of well-defined precatalysts of the NiCl(Ar)(phosphine), 5,6 Ni-(allyl)Cl(phosphine), 7 NiCl(o-tol)(TMEDA), 8,9 and recently highlighted air-stable Ni(COD)(DQ) 10 types as practical alternatives to Ni(COD) 2 .…”

“…Asymmetric transformations continue to attract the interest of many research groups in the area of Ni-catalyzed couplings. The effectiveness of nickel catalysis in coupling of C(sp 3 ) centers provides a great opportunity to introduce chirality induced by chiral ligands. Carbon electrophiles as well as carbon nucleophiles react through racemic intermediates such as radicals or can be racemized at a high rate under the reaction conditions, which then allows for stereoinduction progression controlled or influenced by the chirality of a ligand.…”

“…Asymmetric Catalytic Synthesis of Epoxides via Three-Component Reaction Scheme 8. Asymmetric [3,3] The developed conditions were successfully applied for the preparation of variety of chiral C(3)-substituted indoles in high yields (up to 95%) with high enantioselectivities (up to 96% ee). Enantioselective difunctionalization of alkenes provides an efficient approach to construct complex chiral molecules from relatively simple and readily available starting materials.…”

“…Studies by several research groups, including those of MacMillan, Weix, Reisman, Gong, and others, have established the feasibility and synthetic effectiveness of this chemistry, as highlighted earlier in this review series. 3,4 MacMillan described the use of silanemediated bromine atom abstraction under dual nickel/photoredox catalysis as an alternative approach for the crosselectrophile coupling of aryl bromides and alkyl bromides. 22 Recently, MacMillan's group communicated 23 the modification of the silane substituents to amplify the electron density on an open-shell silicon group, resulting in an increased polarity that is properly tuned for the matching effect between an unactivated C−Cl bond and the silyl abstraction reagent (Scheme 11).…”

“…Another noteworthy reaction is the Cu-catalyzed intramolecular radical enantioconvergent tertiary C(sp 3 )−H amination reported by Liu and co-workers. 49 While enantioselective functionalization of prochiral C(sp 3 )−H bonds is one of the most active research areas in C−H functionalization, the enantioconvergent transformation of racemic tertiary C(sp 3 )− H bonds is still rare.…”