New 2-alkylsulfinyl dithioacetates and thioacetamides have been prepared. The asymmetric synthesis of (R)-2-(cyclohexylsulfinyl)-N,N-dimethylthioacetamide from previously unreported (S)-diacetone-d-glucose cyclohexanesulfinate was achieved in excellent yield (91%) and enantiomeric excess (98%). Methyl (R)-2-(cyclohexylsulfinyl)dithioacetate (98% ee) was obtained from chiral cyclohexyl methyl sulfoxide (99% ee).
Asymmetric Thio-Claisen Rearrangement Induced by an Enantiopure Alkylsulfinyl Group. Unusual Preference for a Boat Transition State in the Acyclic Series
vinylic alkylsulfinyl substituent were readily prepared from (R)-2-cyclohexylsulfinyl-N,N-dimethylethanethioamide 1 with full control of the geometry of their double bonds. They underwent a Claisen rearrangement upon heating at THF reflux to afford alpha-sulfinyl gamma-unsaturated thioamides 3a-c and 6a-b. With all substrates the asymmetric induction of the sulfinyl group was excellent. The determination