Mechanochemical Divergent Syntheses of Oxindoles and α-Arylacylamides via Controllable Construction of C-C and C-N Bonds by Copper and Piezoelectric Materials.

Herein, we present the divergent syntheses of α-arylacylamides and oxindoles via mechanoredox chemistry by using easily accessible α-bromo N-sulfonyl amides as starting materials. Our system consists of a catalytic amount of CuII precatalyst and piezoelectric materials. The highly polarized BaTiO3 or PbTiO3 under mechanical agitation can act as an electron donor to realize the recycling of CuII and CuI . Control experiments and density functional theory calculations have been performed to support the proposed mechanistic rationale for the cascade reactions.

Nickel-catalyzed intermolecular oxidative Heck arylation driven by transfer hydrogenation.

The conventional oxidative Heck reaction between aryl boronic acids and alkenes typically involved the PdII/Pd0/PdII catalytic cycle incorporating an external oxidant and often suffered C=C bond isomerization for internal alkyl-substituted alkenes via chain-walking. Herein, we demonstrate that the regioselectivity (γ-selectivity vs. δ-selectivity) and pathway selectivity (hydroarylation vs. oxidative Heck coupling) of a directed Ni-catalyzed alkene arylation can be controlled by judicious tuning of the coordination environment around the nickel catalyst via optimization of an appropriate phosphine ligand and directing group. In this way, the Ni(0)-catalyzed oxidative Heck arylation that relies on transfer hydrogenation of an acceptor olefin is developed with excellent E/Z selectivity and regioselectivity. Mechanistic investigations suggest that the addition of the acceptor is crucial for lowering the energy for carbometalation and for enabling catalytic turnover.

Nickel(0)-catalyzed linear-selective hydroarylation of unactivated alkenes and styrenes with aryl boronic acids.

Herein, we describe the first linear-selective hydroarylation reaction of unactivated alkenes and styrenes with aryl boronic acids, which was achieved by introducing a directing group on the alkenes. This efficient, scalable reaction serves as a method for modular assembly of structurally diverse alkyl arenes, including γ-aryl butyric acid derivatives, which are widely utilized as chemical building blocks for the synthesis of various drugs and other biologically active compounds.

One-pot synthesis of 2,3-difunctionalized indoles via Rh(iii)-catalyzed carbenoid insertion C-H activation/cyclization.

Reported herein is the first Rh(iii)-catalyzed carbenoid insertion C-H activation/cyclization of N-arylureas and α-diazo ß-keto esters. The redox-neutral reaction has the following features: good to excellent yields, broad substrate/functional group tolerance, exclusive regioselectivity, and no need for additional oxidants or additives, which render this methodology as a more efficient and versatile alternative to the existing methods for the synthesis of 2,3-difunctionalized indoles.

Rhodium(iii)-catalyzed and MeOH-involved regioselective mono-alkenylation of N-arylureas with acrylates.

We herein disclose, for the first time, Rh(iii)-catalyzed and MeOH-involved regioselective mono-alkenylation of arenes with acrylates using NHCONMe2 as the transformable directing group, giving direct access to diverse ortho-acrylated N-phenyl carbamates. The synthetic application of the obtained products to build privileged quinolin-2(1H)-ones and 3-(2-aminophenyl)acrylates has also been demonstrated in subsequent derivatization reactions.