Harunobu Mitsunuma

We describe a hybrid system that realizes cooperativity between an organophotoredox acridinium catalyst and a chiral chromium complex catalyst, thereby enabling unprecedented exploitation of unactivated hydrocarbon alkenes as precursors to chiral allylchromium nucleophiles for asymmetric allylation of aldehydes. The reaction proceeds under visible light irradiation at room temperature, affording the corresponding homoallylic alcohols with a diastereomeric ratio >20/1 and up to 99% ee. The additi

Simple feedstock organic molecules, especially alkenes, are attractive starting materials in organic synthesis because of their wide availability. Direct utilization of such bulk, inert organic molecules for practical and selective chemical reactions, however, remains limited. Herein, we developed a ternary hybrid catalyst system comprising a photoredox catalyst, a hydrogen-atom-transfer catalyst, and a chromium complex catalyst, enabling catalytic allylation of aldehydes with simple alkenes, in

We developed the first acceptorless dehydrogenation of aliphatic secondary alcohols to ketones under visible light irradiation at room temperature by devising a ternary hybrid catalyst system comprising a photoredox catalyst, a thiophosphate organocatalyst, and a nickel catalyst. The reaction proceeded through three main steps: hydrogen atom transfer from the α-C-H bond of an alcohol substrate to the thiyl radical of the photo-oxidized organocatalyst, interception of the generated carbon-centere

Despite the sophistication of C-H functionalization as one of the most powerful tools in organic synthesis, methodology for performing hydrogen-atom transfer of unactivated alkanes remains rather scarce. Herein, we describe chlorine radical-catalyzed C(sp³)-H photoalkylation using titanium(IV) chloride via a ligand-to-metal charge transfer process. Enabled by the unique properties of this abundant metal salt, the reaction not only effected the coupling of various alkanes with radical

A homodinuclear Ni(2)-Schiff base 1 complex (1-10 mol%) promoted the catalytic asymmetric 1,4-addition reactions of β-keto esters and an N-Boc oxindole to nitroethylene, giving products in 98-75% ee.

We developed a chromium-catalyzed, photochemical, and linear-selective alkylation of aldehydes with alkylzirconium species generated <i>in situ</i> from a wide range of alkenes and Schwartz's reagent. Photochemical homolysis of the C-Zr bond afforded alkyl radicals, which were then trapped by a chromium complex catalyst to generate the alkylchromium(III) species for polar addition to aldehydes. The reaction proceeded with high functional group tolerance at ambient temperature under visible-light

Asymmetric catalysis enabling divergent control of multiple stereocenters remains challenging in synthetic organic chemistry. Although machine-learning-based optimization of molecular catalysis is a rapidly growing research field, the use of such approaches for catalyst design to achieve stereodivergent asymmetric synthesis producing multiple reaction outcomes, such as constitutional selectivity, diastereoselectivity, and enantioselectivity, is unprecedented. Here, we report the straightforward

Direkter Zugang: Sterisch gehinderte vicinale quartäre Kohlenstoffstereozentren wurden mithilfe einer katalytischen enantio- und diastereoselektiven doppelten Michael-Reaktion aufgebaut, die direkten Zugang zu dimeren Hexahydropyrroloindol-Alkaloiden ermöglicht. Ein Mn(4-Fluorbenzoat)2/Schiff-Base-Komplex und ein Mg(OAc)2/Benzoesäure-System wurden als Katalysatoren verwendet.

Hydroxyalkylation of <i>N</i>-heteroaromatics with aldehydes was achieved using a binary hybrid catalyst system comprising an acridinium photoredox catalyst and a thiophosphoric acid organocatalyst. The reaction proceeded through the following sequence: (1) photoredox-catalyzed single-electron oxidation of a thiophosphoric acid catalyst to generate a thiyl radical, (2) cleavage of the formyl C-H bond of the aldehyde substrates by a thiyl radical acting as a hydrogen atom transfer catalyst to gen

Abstract Organochromium(III) species are versatile nucleophiles in complex molecule synthesis due to their high functional group tolerance and chemoselectivity for aldehydes. Traditionally, carbonyl addition reactions of organochromium(III) species were performed through reduction of organohalides either using stoichiometric chromium(II) salts or catalytic chromium salts in the presence of stoichiometric reductants [such as Mn(0)]. Recently, alternative methods emerged involving organoradical fo

We developed organocatalyst systems to promote the cleavage of stable C-H bonds, such as formyl, α-hydroxy, and benzylic C-H bonds, through a hydrogen atom transfer (HAT) process without the use of exogenous photosensitizers. An electronically tuned thiophosphoric acid, 7,7'-OMe-TPA, was assembled with substrate or co-catalyst <i>N</i>-heteroaromatics through hydrogen bonding and π-π interactions to form electron donor-acceptor (EDA) complexes. Photoirradiation of the EDA complex induced stepwis

We identified a ternary hybrid catalyst system composed of an acridinium photoredox catalyst, a thiophosphoric imide (TPI) catalyst, and a titanium complex catalyst that promoted an intermolecular addition reaction of organic molecules with various ketones through sp³ C-H bond activation. The thiyl radical generated via single-electron oxidation of TPI by the excited photoredox catalyst abstracted a hydrogen atom from organic molecules such as toluene, benzyl alcohol, alkenes, aldehyd

The catalytic asymmetric aldol reaction is among the most useful reactions in organic synthesis. Despite the existence of many prominent reports, however, the late-stage, chemoselective, catalytic, asymmetric aldol reaction of multifunctional substrates is still difficult to achieve. Herein, we identified that in situ pre-conversion of carboxylic acids to siloxy esters facilitated the boron-catalyzed direct aldol reaction, leading to the development of carboxylic acid-selective, catalytic, asymm

The advancement of an effective hydrogen liberation technology from liquid organic hydrogen carriers, particularly cycloalkanes such as cyclohexane and methylcyclohexane, holds significance in realizing a hydrogen-centric society. However, the attainment of homogeneous catalytic acceptorless dehydrogenation characterized by elevated selectivity for thorough aromatization under mild conditions remains unrealized. In this study, a catalyst system, facilitated by a double hydrogen atom transfer pro

Abstract The catalytic asymmetric aldol reaction is among the most useful reactions in organic synthesis. Despite the existence of many prominent reports, however, the late‐stage, chemoselective, catalytic, asymmetric aldol reaction of multifunctional substrates is still difficult to achieve. Herein, we identified that in situ pre‐conversion of carboxylic acids to siloxy esters facilitated the boron‐catalyzed direct aldol reaction, leading to the development of carboxylic acid‐selective, catalyt