Configurational Stability of Optically Active Dichloromethyl p-Tolyl Sulfoxide and Its Anionic Species: Experimental and Theoretical Study

Racemization of optically active dichloromethyl p-tolyl sulfoxide took place at −78°C in the presence of potassium bis(trimethylsilyl)amide (KHMDS), while the same racemization did not occur under reflux in toluene in the absence of KHMDS. Density functional theory calculations suggested that the pyramidal inversion at the sulfur center was unlikely to be involved in the racemization mechanism. An anionic species of the sulfoxide was found to be gradually converted into chlorobis(p-tolylsulfinyl)methane and dichlorocarbene. We propose a racemization mechanism mediated by achiral potassium p-toluenesulfenate and chloro(p-tolylsulfinyl)methylene. © 2013 Wiley Periodicals, Inc. Heteroatom Chem 24:131–137, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.21074

[1]  T. Satoh.  Recent Advances in the Chemistry and Synthetic Uses of Magnesium Carbenoids , 2012 .

[2]  T. Satoh,et al.  Synthesis, including asymmetric synthesis, of 3-oxabicyclo[3.1.0]hexanes and bicyclo[3.1.0]hexanes by the 1,5-CH insertion of cyclopropylmagnesium carbenoids as the key reaction , 2012 .

[3]  M. Tadokoro,et al.  The first example for the asymmetric synthesis of allenes by the Doering–LaFlamme allene synthesis with enantiopure cyclopropylmagnesium carbenoids , 2011 .

[4]  S. Gronert,et al.  Stabilities of carbenes: independent measures for singlets and triplets. , 2011, Journal of the American Chemical Society.

[5]  I. Agranat,et al.  Racemization of the gastrointestinal antisecretory chiral drug esomeprazole magnesium via the pyramidal inversion mechanism: A theoretical study. , 2010, Chirality.

[6]  T. Satoh,et al.  The first example of racemization of the sulfur stereogenic center of α-sulfinyl carbanions at low temperatures , 2010 .

[7]  A. Kalir,et al.  Biological activity of sulfoxides and sulfones , 2010 .

[8]  T. Satoh,et al.  Resolution of racemic aryl dichloromethyl sulfoxides with (−)-menthone , 2009 .

[9]  M. M. Ferreira,et al.  Theoretical study of omeprazole behavior: Racemization barrier and decomposition reaction , 2008 .

[10]  T. Satoh.  Recent advances in the chemistry of magnesium carbenoids. , 2007, Chemical Society reviews.

[11]  I. Agranat,et al.  Pyramidal inversion mechanism of simple chiral and achiral sulfoxides: a theoretical study. , 2007, Chirality.

[12]  O. Lanzalunga,et al.  Thermal and photochemical racemization of chiral aromatic sulfoxides via the intermediacy of sulfoxide radical cations. , 2007, Organic letters.

[13]  H. Pellissier.  Use of Chiral Sulfoxides in Asymmetric Synthesis , 2006 .

[14]  C. Bolm,et al.  Applications of Catalytic Asymmetric Sulfide Oxidations to the Syntheses of Biologically Active Sulfoxides , 2005 .

[15]  F. Maseras,et al.  Base-catalyzed inversion of chiral sulfur centers. A computational study. , 2004, Organic letters.

[16]  N. Khiar,et al.  Recent developments in the synthesis and utilization of chiral sulfoxides. , 2003, Chemical reviews.

[17]  M. Mąkosza,et al.  Vicarious nucleophilic substitution of hydrogen in nitrophenyl toluenesulfonates , 1997 .

[18]  T. Satoh.  Oxiranyl Anions and Aziridinyl Anions. , 1996, Chemical reviews.

[19]  M. Frisch,et al.  Using redundant internal coordinates to optimize equilibrium geometries and transition states , 1996, J. Comput. Chem..

[20]  M. C. Carreño,et al.  Applications of Sulfoxides to Asymmetric Synthesis of Biologically Active Compounds , 1995 .

[21]  C. Rizzoli,et al.  .alpha.-Sulfinyl transition metal bond. 1. Naked .alpha.-sulfinyl anions and their reactivity with metal carbonyls: synthesis of metal-carbon bonded .alpha.-sulfinyls and .alpha.-sulfinylcarbenes , 1993 .

[22]  K. R. Rao,et al.  Asymmetric synthesis of α,α-dichlorosulphoxides from substituted thioacetates and sodium hypochlorite in β-cyclodextrin complexes , 1989 .

[23]  K. Yamakawa,et al.  The practical procedure for a preparation of 1-chloroalkyl p-tolyl sulfoxides in high optically active form: A very short synthesis of optically active disparlure , 1988 .

[24]  W. Massa,et al.  [α‐(Phenylsulfinyl)‐α‐methylbenzyllithium‐tetramethylethylenediamine]2: Crystal Structure of an α‐Sulfinyl “Carbanion” , 1986 .

[25]  J. Tillett.  Nucleophilic substitution at tricoordinate sulfur , 1976 .

[26]  G. Scorrano,et al.  Novel route to racemization of sulfoxides , 1972 .

[27]  K. Mislow,et al.  Thermal racemization of diaryl, alkyl aryl, and dialkyl sulfoxides by pyramidal inversion , 1968 .

[28]  E. Miller,et al.  Thermal racemization of benzyl p-tolyl sulfoxide and thermal rearrangement of benzyl p-toluenesulfenate , 1968 .

[29]  E. Miller,et al.  Mechanisms of Thermal Racemization of Sulfoxides1 , 1966 .