SINGLE-STEP CONVERSION OF CHIRAL CARNITINE AND DERIVATIVES INTO (S)-BETA-SUBSTITUTED-GAMMA-BUTYROLACTONES AND (R)-BETA-SUBSTITUTED-GAMMA-BUTYROLACTONES

This paper describes an efficient single step transformation of chiral carnitine and carnitine derivatives into stereoisomerically pure (S)- and (R)-beta-substituted-gamma-butyrolactones, obtained by intramolec ular nucleophilic displacement. (S)- Or (R)-carnitine and (R)-aminocar nitine inner salts give beta-hydroxy-gamma-butyrolactone and beta-amin o-gamma-butyrolactone respectively (82% and 77%) with the same configu ration as the starting material. (R)-Acetylaminocarnitine inner salt g ives (R)-beta-acetylamino-gamma-butyrolactone (90%), while (R)-acetylc arnitine gives 2(5H)-furanone under the same reaction conditions (77%, via cyclization and subsequent elimination reaction). (R)-N-Benzyloxy carnitineamide gives a mixture of pyrrolidinone (11%) and furanoyl imi date (50%) derivatives. The direct transformation of waste (S)-carniti ne into the valuable (S)-beta-hydroxy-gamma-butyrolactone or (after ac etylation) into the precious 2(5H)-furanone is of particular interest.