Synthese und Reaktionen chiraler, von (R)-(?)-bzw. (S)-(+)-2-Methoxymethylpyrrolidin abgeleiteter Dithiocarbamate

Abstract

Synthesis and Reactions of Chiral Dithiocarbamates Derived from (R)-(−)- or (S)-(+)-2- The synthesis, diastereoselective alkylation reactions, dithiocarboxylation, and aldol condensation of several substituted methyl (R1CH2) (S)-2-(methoxymethyl)-pyrrolidine-1-dithiocarboxylates (S)-2 and of the corresponding (R)-derivatives (R)-2 are described. The new enantiomeric dithiocarbamates (S)-2a–e, and (R)-2a–d are obtained by reaction of (S)-(+)-[(S)-1] or (R)-(−)-2-(methoxymethyl)-pyrrolidine [(R)-1], respectively, with carbon disulfide in dry methanol/anhydrous sodium acetate and the appropriate alkylating agent. The cyclic ketene dithioacetals (S)-3 and (R)-3 are formed by dithiocarboxylation procedure of (S)-2a and (R)-2a whereas (S)-6 and (R)-6 are obtained by aldol reaction with isobutyraldehyde. (S)-2c,d and (R)-2c,d react in a diastereoselective manner after deprotonation with n-BuLi or LiTMP/LiBr at −78°C in THF with alkyl halides to the enantiomeric compounds 4a/ent-4a, 4b/ent-4b and 5/ent-5, respectively.