Synthesis of enantiomerically pure alkyl and aryl methyl sulfoxides from cholesteryl methanesulfinates

Localized Partitioning of Enantiomers in Solid Samples of Sulfoxides: Importance of Sampling Method in Determination of Enantiopurity

“…Synthesis of enantioenriched sulfoxides is undertaken primarily employing two principal strategies, nucleophilic displacement from sulfinate precursors and asymmetric sulfoxidation of prochiral sulfides mediated by transition metal catalysts. ,− Extensive reports of asymmetric sulfur oxidation have appeared over the past 30 years since the seminal reports from Kagan , and Modena utilizing titanium mediated oxidation.…”

A new enzymatic enantioselective synthesis of dialkyl sulfoxides catalysed by monooxygenases

“…This process requires a separation of diastereoisomers which are then treated with the relevant alkyl Grignard reagent to furnish the optically active sulfoxide. 3 Similarly, diacetone-d-glucose (DAG) has been used to induce chirality at sulfur. 4 Reaction of diastereoisomerically pure DAG-alkyl sulfinates with Grignard reagents gives optically active dialkyl sulfoxides with high ee (up to !98%).…”

“…For CMO promoted sulfoxidation, high enantioselectivity is observed for cycloalkyl methyl sulfoxides (1, 2), and methyl sulfoxides with a linear or branched alkyl chain of up to four carbon atoms (3,6,7). In all these cases the absolute configuration of the prevailing enantiomer is R. A longer alkyl chain not only causes a drastic drop in the chemical and optical yield 4, 5, but also changes the stereochemical course of the sulfoxidation, since the resulting enantiomer now has the S absolute configuration.…”

Synthesis of enantioenriched sulfoxides

“…8 Andersen et al published a procedure for the synthesis of pure methyl alkyl sulfoxides using cholesterol as the leaving group instead of menthol. 242 Using cholesterol allowed preparation of the epimeric mixture of enantiomerically pure methyl sulfinate esters 207 suitable for nucleophilic substitution (Scheme 101). Dialkyl sulfoxides with high enantiomeric purity were obtained, generally in excess of 80% ee, albeit with poor yields; typically less than 50%.…”