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Sulfondiimines are diaza-analogues of sulfones with a chiral sulfur center. Compared to sulfones and sulfoximines, their synthesis and transformations have so far been studied to a lesser extent. Here, we report the enantioselective synthesis of 1,2-benzothiazine 1-imines, i.e., cyclic sulfondiimine derivatives from sulfondiimines and sulfoxonium ylides via C-H alkylation/cyclization reactions. The combination of [Ru(p-cymene)Cl 2 ] 2 and a newly developed chiral spiro carboxylic acid is key to achieving high enantioselectivity., (© 2023 Wiley-VCH GmbH.)

The synthesis, characterization, and catalytic performance of an iridium(III) catalyst with an electron-deficient cyclopentadienyl ligand ([Cp E IrI 2 ] 2 ) are reported. The [Cp E IrI 2 ] 2 catalyst was synthesized by complexation of a precursor of the Cp E ligand with [Ir(cod)OAc] 2 , followed by oxidation, desilylation, and removal of the COD ligand. The electron-deficient [Cp E IrI 2 ] 2 catalyst enabled C-H amidation reactions assisted by a weakly coordinating ether directing group. Experimental mechanistic studies and DFT calculations suggested that the high catalytic performance of [Cp E IrI 2 ] 2 is due to its electron-deficient nature, which accelerates both C-H activation and Ir V -nitrenoid formation., (© 2023 Wiley-VCH GmbH.)

Due to its mild reaction conditions and unique chemoselectivity, hydrogen atom transfer (HAT) hydrogenation represents an indispensable method for the synthesis of complex molecules. Its analog using deuterium, deuterium atom transfer (DAT) deuteration, is expected to enable access to complex deuterium-labeled compounds. However, DAT deuteration has been scarcely studied for synthetic purposes, and a method that possesses the favorable characteristics of HAT hydrogenations has remained elusive. Herein, we report a protocol for the photocatalytic DAT deuteration of electron-deficient alkenes. In contrast to the previous DAT deuteration, this method tolerates a variety of synthetically useful functional groups including haloarenes. The late-stage deuteration also allows access to deuterated amino acids as well as donepezil-d 2 . Thus, this work demonstrates the potential of DAT chemistry to become the alternative method of choice for preparing deuterium-containing molecules., (© 2022 Wiley-VCH GmbH.)

Trivalent group-9 metal catalysts with a cyclopentadienyl-type ligand (CpM III ; M=Co, Rh, Ir, Cp=cyclopentadienyl) have been widely used for directed C-H functionalizations, albeit that their application to challenging C(sp 3 )-H functionalizations suffers from the limitations of the available directing groups. In this report, we describe directed C(sp 3 )-H amidation reactions of simple amide substrates with a variety of substituents. The combination of an electron-deficient Cp E Rh catalyst (Cp E =1,3-bis(ethoxycarbonyl)-substituted Cp) and an electron-deficient 2-pyridone ligand is essential for high reactivity., (© 2022 Wiley-VCH GmbH.)

Among sulfoximine derivatives containing a chiral sulfur center, benzothiadiazine-1-oxides are important for applications in medicinal chemistry. Here, we report that the combination of an achiral cobalt(III) catalyst and a pseudo-C 2 -symmetric H 8 -binaphthyl chiral carboxylic acid enables the asymmetric synthesis of benzothiadiazine-1-oxides from sulfoximines and dioxazolones via enantioselective C-H bond cleavage. With the optimized protocol, benzothiadiazine-1-oxides with several functional groups can be accessed with high enantioselectivity., (© 2022 Wiley-VCH GmbH.)

The synthesis, characterization, and catalytic performance of iridium(III) catalysts that bear an amide-pendant cyclopentadienyl ligand ([Cp A IrI 2 ] 2 ) is reported. These [Cp A IrI 2 ] 2 catalysts were obtained from the complexation of a Cp A ligand precursor with [Ir(cod)OAc] 2 followed by oxidation. Double aromatic homologation reactions of benzamides with alkynes by fourfold C-H activation proceeded in good to high yield with these [Cp A IrI 2 ] 2 catalysts, demonstrating their superior catalytic performance in this challenging transformation., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Catalytic enantioselective directed methylene C(sp 3 )-H amidation reactions of 8-alkylquinolines using a Cp*Rh III /chiral carboxylic acid (CCA) hybrid catalytic system are described. A binaphthyl-based chiral carboxylic acid efficiently differentiates between the enantiotopic methylene C-H bonds, which leads to the formation of C-N bonds with good enantioselectivity., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Co-catalyzed allylic substitution reactions have received little attention, arguably because of the lack of any known advantage of Co catalysis over either Rh or Ir catalysis. Described here is a general and regioselective Co-catalyzed allylic alkylation using an in situ catalyst activation by organophotoredox catalysis. This noble-metal-free catalytic system exhibits unprecedentedly high reactivities and regioselectivities for the allylation with an allyl sulfone, for the first time, representing the unique synthetic utility of the Co-catalyzed method compared to the related Rh- and Ir-catalyzed reactions., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Recent advances in Cp x M III catalysis (M=Co, Rh, Ir) have enabled a variety of enantioselective C(sp 2 )-H functionalization reactions, but enantioselective C(sp 3 )-H functionalization is still largely unexplored. We describe an asymmetric C(sp 3 )-H amidation of thioamides using an achiral Co III /chiral carboxylic acid hybrid catalytic system, which provides easy and straightforward access to chiral β-amino thiocarbonyl and β-amino carbonyl building blocks with a quaternary carbon stereocenter., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Catalytic acceptorless dehydrogenation is an environmentally benign way to desaturate organic compounds. This process is traditionally accomplished with transition-metal-based catalysts. Herein, a borane-catalyzed, metal-free acceptorless dehydrogenation of saturated N-heterocycles is disclosed. Tris(pentafluorophenyl)borane was identified as a versatile catalyst, which afforded several synthetically important N-heteroarenes in up to quantitative yield. Specifically, the present metal-free catalytic system exhibited a uniquely high tolerance toward sulfur functionalities, and demonstrated superior reactivity in the synthesis of benzothiazoles compared to conventional metal-catalyzed systems. This protocol can thus be regarded as the first example of metal-free acceptorless dehydrogenation in synthetic organic chemistry., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)