An Improved Synthesis of (S)-Aspartyl-(7,7-Dimethylnorborn-2R-yl)-(S)-Alanine Methyl Esters, A New High Intensity Artificial Sweetener

Article abstract of DOI:10.1016/S0040-4020(01)88486-6

(S)-Aspartyl-(7,7-dimethylnorborn-2R-yl)-(S)-alanine methyl ester (1) was synthesized in nine steps from (+)-α-fenchyl alcohol (3) as a chiral synthon.Crucial steps for controlling the side-chain stereochemistry of 1, required for the manifestation of sweentness, were the catalytic hydroformylation of the olefin 4 and the enzymatic resolution of the racemic amino acid 9 using acylase I. Key Words: sweetener, (+)-α-fenchyl alcohol, (+)-α-fenchene, catalytic hydroformylation, enzymatic resolution.