Lipase‐Catalyzed Enantiomer Separation of 3‐Hydroxy‐4‐(tosyloxy)butanenitrile: Synthesis of (R)‐GABOB (=(3R)‐4‐Amino‐3‐hydroxybutanoic Acid) and (R)‐Carnitine Hydrochloride (=(2R)‐3‐Carboxy‐2‐hydroxy‐N,N,N‐trimethylpropan‐1‐aminium Chloride)

Abstract Enzymatic resolution of racemic 3‐hydroxy‐4‐(tosyloxy)butanenitrile ((±)‐ 5 ) by using various lipases in different solvents were studied. The obtained optically pure (3 R )‐3‐(acetyloxy)‐4‐(tosyloxy)butanenitrile (( R )‐ 6 ), upon treatment with aqueous ammonia followed by conc. HCl solution, provided ( R )‐GABOB (=(3 R )‐4‐amino‐3‐hydroxybutanoic acid; ( R )‐ 1 ). Similarly, reaction of ( R )‐ 6 with aqueous trimethylamine solution followed by conc. HCl solution provided ( R )‐carnitine hydrochloride (=(2 R )‐3‐carboxy‐2‐hydroxy‐ N , N , N ‐trimethylpropan‐1‐aminium chloride; ( R )‐ 2 ⋅HCl) in an expeditious manner.