SYNTHESIS AND REACTIONS OF CHIRAL DITHIOC ARBAMATES DERIVED FROM (R)-(-)- OR (S)-(-2-())

The synthesis, diastereoselective alkylation reactions, dithiocarboxyl ation, and aldol condensation of several substituted methyl (R(1)-CH2) (S)-2-(methoxymethyl)-pyrrolidine-1 -dithiocarboxylates (S)-2 and of the corresponding (R)-derivatives (R)-2 are described. The new enantio meric 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 a cetate and the appropriate alkylating agent. The cyclic ketene dithioa cetals (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 reacti on with isobutyraldehyde. (S)-2c,d and (R)-2c,d react in a diastereose lective manner after deprotonation with n-BuLi or LiTMP/LiBr at -78 de grees C in THF with alkyl halides to the enantiomeric compounds 4a/ent -4a, 4b/ent-4b and 5/ent-5, respectively.