Nickel‐Mediated Photoreductive Cross Coupling of Carboxylic Acid Derivatives for Ketone Synthesis**

A simple photochemical, nickel-catalyzed synthesis of ketones starting from carboxylic acids is presented. Hantzsch-ester (HE) functions as a cheap, green and strong photoreductant upon visible-light excitation to facilitate radical generation and also engages in the Ni-catalytic cycle to restore the reactive species. With this dual role, HE allows for the coupling of a large variety of radicals (1°,2°, benzylic, α-oxy & α-amino) with aroyl and alkanoyl moieties, a new feature in the synthesis of ketones through dual nickel photoredox catalysis. With both precursors deriving from abundant carboxylic acids, this protocol is a welcome addition to the organic chemistry toolbox. The reactio…

One-Pot Synthesis of Pyrrole-2-carboxylates and -carboxamides via an Electrocyclization/Oxidation Sequence

An electrocyclic ring closure is the key step of an efficient one-pot method for the synthesis of pyrrole-2-carboxylates and -carboxamides from chalcones and glycine esters or amides. The 3,4-dihydro-2H-pyrrole intermediates generated in situ are oxidized to the corresponding pyrroles by stoichiometric oxidants or by catalytic copper(II) and air in moderate to high yields. A wide range of functional groups are tolerated, and further combination with an in situ bromination gives access to polyfunctional pyrrole scaffolds.

A Photoredox-Catalyzed Four Component Reaction for the Atom-Efficient Synthesis of Complex Secondary Amines

The one-pot sulfonylation/aminoalkylation of styrene derivatives furnishing highly substituted gamma-sulfonylamines was accomplished through a photoredox-catalyzed four-component reaction. Apart from one molecule of water and the sodium counterion of the sulfinate, all atoms of the starting materials are transferred to the final product, rendering this process highly atom-efficient. The operationally simple protocol allows for the simultaneous formation of three new single bonds (C–S, C–N, and C–C) and therefore grants rapid access to structurally diverse products. The reaction proceeds under mild conditions in aqueous acetonitrile and shows a broad scope, including natural products and dru…

Visible Light-Induced Sulfonylation/Arylation of Styrenes in a Double Radical Three-Component Photoredox Reaction

Simultaneous sulfonylation/arylation of styrene derivatives is achieved in a photoredox-catalyzed three-component reaction using visible light. A broad variety of difunctionalized products is accessible in mostly excellent yields and high diastereoselectivity. The developed reaction is scalable and suitable for the modification of styrene-functionalized biomolecules. Mechanistic investigations suggest the transformation to be operating through a designed sequence of radical formation and radical combination.

Front Cover: Visible‐Light‐Induced Cleavage of C−S Bonds in Thioacetals and Thioketals with Iodine as a Photocatalyst (ChemPhotoChem 2/2020)

Photoredox-Catalyzed Four-Component Reaction for the Synthesis of Complex Secondary Amines.

The one-pot sulfonylation/aminoalkylation of styrene derivatives furnishing substituted γ-sulfonylamines was accomplished through a photoredox-catalyzed four-component reaction. Besides one molecule of water and the sodium counterion of the sulfinate, all atoms of the starting materials are transferred to the final product, rendering this process highly atom-efficient. The operationally simple protocol allows for the simultaneous formation of three new single bonds (C-S, C-N, and C-C) and therefore grants rapid access to structurally diverse products.

Visible‐Light‐Induced Cleavage of C−S Bonds in Thioacetals and Thioketals with Iodine as a Photocatalyst

Cover Feature: Visible Light‐Induced Sulfonylation/Arylation of Styrenes in a Double Radical Three‐Component Photoredox Reaction (Chem. Eur. J. 38/2019)

ChemInform Abstract: One-Pot Synthesis of Pyrrole-2-carboxylates and -carboxamides via an Electrocyclization/Oxidation Sequence.

An electrocyclic ring closure is the key step of an efficient one-pot method for the synthesis of pyrrole-2-carboxylates and -carboxamides from chalcones and glycine esters or amides. The 3,4-dihydro-2H-pyrrole intermediates generated in situ are oxidized to the corresponding pyrroles by stoichiometric oxidants or by catalytic copper(II) and air in moderate to high yields. A wide range of functional groups are tolerated, and further combination with an in situ bromination gives access to polyfunctional pyrrole scaffolds.

CCDC 1891336: Experimental Crystal Structure Determination

Related Article: Benjamin Lipp, Lisa Marie Kammer, Murat Kücükdisli, Adriana Luque, Jonas Kühlborn, Stefan Pusch, Gita Matulevičiūtė, Dieter Schollmeyer, Algirdas Šačkus, Till Opatz|2019|Chem.-Eur.J.|25|8965|doi:10.1002/chem.201901175

CCDC 1055316: Experimental Crystal Structure Determination

Related Article: Dennis Imbri , Natalie Netz , Murat Kucukdisli , Lisa Marie Kammer , Philipp Jung , Annika Kretzschmann , and Till Opatz|2014|J.Org.Chem.|79|11750|doi:10.1021/jo5021823

CCDC 1055315: Experimental Crystal Structure Determination

Related Article: Dennis Imbri , Natalie Netz , Murat Kucukdisli , Lisa Marie Kammer , Philipp Jung , Annika Kretzschmann , and Till Opatz|2014|J.Org.Chem.|79|11750|doi:10.1021/jo5021823