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Synlett 2008(9): 1423-1424  
DOI: 10.1055/s-2008-1067009
SPOTLIGHT
© Georg Thieme Verlag Stuttgart · New York

Dimethylsulfoxonium Methylide (DSM): A Versatile Reagent

Chhama Awasthi*
Green Synthesis Lab, Department of Chemistry, University of Allahabad, Allahabad - 211002, U.P., India
e-Mail: chhama-awasthi@hotmail.com;

Dedicated to my honorable mentor Prof. L. D. S. Yadav


Further Information

Publication History

Publication Date:
07 May 2008 (online)

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Biographical Sketches

Chhama Awasthi was born in Kanpur, U.P., India in 1983. She received her M.Sc. degree (2006) in Chemistry from the University of Allahabad, India. In the same year, she joined the research group of Prof. L. D. S. Yadav as Ph.D. student. She has qualified for CSIR-UGC in the National Eligibility Test (NET) in 2007. Her research is focused on the development of new synthetic methodologies placing emphasis on green chemistry.

Introduction

Dimethylsulfoxonium methylide (DSM), also known as Corey-Chaykovsky reagent, has proved to be a versatile nucleophilic reagent capable of reacting with different chemical systems. Its industrial availability coupled with its potential to achieve original chemical transformations makes it a reagent of choice for the synthesis of new leads and innovative substances. It has found wide application in organic synthesis such as epoxidation, [1] cyclopropanation, [2] [3] aziridination, [4] extension of esters, [5] diolefination of cycloalkanones, [6] ring transformation, [7] polymerization, [8] formation of silyl enol ethers, [9] ring opening, [10] [11] and formation of chiral spiro[2.5]octanones by methylenation of cyclohexanones. [12]

Preparation

In 1962, Corey and Chaykovsky performed the synthesis of dimethylsulfoxonium methylide 2 by proton transfer of readily accessible trimethylsulfoxonium halides 1 to a strong base. Solutions of 2 in dimethyl sulfoxide were prepared from the iodide (or chloride) 1 by stirring with one equivalent of powdered sodium hydride under nitrogen at room temperature (rapid evolution of hydrogen, exothermic). [13]

Scheme 1

Abstract

(A) Epoxidation: Recently, Hansen and co-workers have reported a DSM-promoted tandem aldol-epoxidation reaction which constructs three new stereocenters with complete diastereoselectivity. [1]

(B) Cyclopropanation: One-pot oxidative cyclopropanation reactions of activated alcohols can be brought about by DSM. [2]

(C) Aziridination: Dimethylsulfoxonium methylide affords difluoromethylaziridines upon reaction with difluoro enamines. [4]

(D) Extension of Esters: Using dimethylsulfoxonium methylide, a variety of methyl esters can be converted into α-chloro ketones with extension of the carbon chain. [5]

(E) Diolefination of Cycloalkanones: Terminal/exocyclic 1,3-dienes are widely used in synthetic organic chemistry. Very recently, Butova and co-workers have synthesized exocyclic 1,3-dienes by a one-pot diolefination of cyclic ketones employing DSM and excess of a base at 130 °C. Under these conditions the Corey reaction is suppressed and terminal 1,3-dienes are formed instead of epoxides. This reaction is termed as Yurchenko diolefination. [6]

(F) Ring Transformation: Coumarin derivatives with electron-withdrawing group at position 3 have been reported to undergo a novel ring transformation with DSM, which has been applied to the second-generation synthesis of ()-linderol A. [7]

(G) Polymerization: Trialkyl and triaryl organoboranes undergo multiple, repetitive homologation upon reaction with DSM. The polyhomologation of 1-boraadamantane·THF with DSM generates a novel macrocyclic trialkylborane, which upon oxidation affords three-armed star poly­methylene polymer incorporating a cis,cis-1,3,5-trisubstituted cyclohexane core. [8]

(H) Formation of Silyl Enol Ethers: Dimethylsulfoxonium methylide has been demonstrated to react with mono- and difluoroacetyltrialkylsilanes to give enol silyl ether products exclusively. [9]

(I) Ring Opening: N-Tosyl-protected 3-hydroxypyrrolidines are prepared by reaction of DSM with readily available epoxysulfonamides via regioselective ring-opening followed by 5-exo-tet cyclization in preference to oxetane formation. [10]