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

ABSTRACT 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