An efficient, economic and environmentally friendly enantioselective oxidation of racemic benzoins (α-hydroxy ketones) catalyzed by a chiral iron complex has been developed using molecular oxygen as a terminal oxidant with good selectivity and excellent enantiomeric excess. © 2009 The Royal Society of Chemistry.

Govindasamy Sekar

Department Of Chemistry

BENZOIN

iron complex

oxidizing agent

article

catalysis

chirality

enantiomer

Enantioselectivity

oxidation

quantum yield

reaction analysis

reaction time

stereochemistry

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IIT Madras

Chemical Communications

An efficient catalytic method has been developed for the synthesis of N-aroylated sulfoximines from readily available toluenes (methylarenes) as source of the aroyl coupling partner and NH-sulfoximines, employing an environmentally benign iron catalyst. This protocol involves oxidation of benzylic C-H bonds of toluenes to generate aroyl radical intermediates followed by oxidative coupling with NH-sulfoximines to form N-aroylated sulfoximines in good to excellent yields. The intermediate aroyl radical is successfully trapped with TEMPO to prove the radical pathway of the reaction. © Georg Thieme Verlag.

Fulltext

Synthesis (Germany)

Iron-Catalyzed One-Pot N-Aroylation of NH-Sulfoximines with Methylarenes through Benzylic C-H Bond Oxidation

An efficient, green and first catalytic process has been developed for the direct synthesis of amides from readily available petroleum by-products (methylarenes) and amines using an iron catalyst. In this new catalytic reaction, the methyl group of the methylarene is oxidized to the corresponding aldehyde through non-directed C-(sp-3)-H oxidation followed by its oxidative amidation with N-chloroamine, yielding the carboxylic amide. Oxidation with an iron catalyst, tert-butyl hydroperoxide (TBHP) as sole oxidant, the synthesis of amides under mild reaction conditions and the utilization of methylarenes as starting material make this methodology novel and environmentally benign. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Advanced Synthesis and Catalysis

Iron-catalyzed direct synthesis of amides from methylarenes

Biologically important bisindolylmethanes are synthesized in a domino fashion by using an iron(II) chloride-(±)-1,1′-binaphthyl-2, 2′-diamine [FeCl2-(±)-BINAM] complex as the catalyst. This method proceeds via oxidation of a primary alcohol into the corresponding aldehyde followed by nucleophilic addition of an indole in the presence of the catalyst. A reaction intermediate is synthesized separately and converted into the bisindolylmethane product under the same reaction conditions as support for the proposed mechanism. © Georg Thieme Verlag Stuttgart · New York.

Iron(II) chloride-1,1′-binaphthyl-2,2′-diamine (FeCl 2-BINAM) complex catalyzed domino synthesis of bisindolylmethanes from indoles and primary alcohols

Selectivity between primary and secondary alcohols was observed in oxidation using whole cells of Candida parapsilosis ATCC 7330, where the secondary alcohol was preferentially oxidized. In racemic sec alcohols, the 'R' enantiomer was selectively oxidized to the corresponding keto alcohol (yield = 18-54%) leaving the 'S' diol (yield = 31-69% and enantiomeric excess from 14% to >99%). A biphasic system consisting of isooctane-water (48 : 2 v/v) was used as a medium for biotransformation at 25 °C. This is the first report of the regio- and enantio-selective oxidation of diols using C. parapsilosis ATCC 7330. © The Royal Society of Chemistry 2014.

RSC Advances

Regio- and enantio-selective oxidation of diols by Candida parapsilosis ATCC 7330

An ironO-catalyzed (TEMPO = 2,2,6,6-tetramethyl-1-piperidinyloxy), aerobic process was developed to synthesize α-keto amides. This reaction proceeds through a domino alcohol oxidation/oxidative cross-dehydrogenative coupling sequence, uses 2-hydroxyacetophenones and amines as the starting materials, and takes place under molecular oxygen, which makes the transformation highly efficient, practical, and environmentally friendly. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

European Journal of Organic Chemistry

IronO-Catalyzed Domino Aerobic Alcohol Oxidation/Oxidative Cross-Dehydrogenative Coupling for the Synthesis of α-Keto Amides

Angewandte Chemie International Edition

Preview: Angew. Chem. Int. Ed. 45/2008

Journal of Molecular Catalysis A: Chemical

Oxidative kinetic resolution of racemic secondary alcohols catalyzed by resin supported sulfonato-Mn(salen) complex in water

The Journal of Organic Chemistry

Dynamic Kinetic Resolution of Benzoins by Lipase−Metal Combo Catalysis

Journal of the American Chemical Society

Vanadium-Catalyzed Asymmetric Oxidation of α-Hydroxy Esters Using Molecular Oxygen as Stoichiometric Oxidant

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Chiral iron complex catalyzed enantioselective oxidation of racemic benzoins

Journal	Chemical Communications
ISSN	13597345
Open Access	No