Enantioselective microbial reduction of 2-oxo-2-(1', 2', 3', 4'-tetrahydro-1', 1', 4', 4'-tetramethyl-6'-naphthalenyl)acetic acid and its ethyl ester

Abstract The chiral ester ethyl (2 R )-hydroxy-2-(1′,2′,3′,4′-tetrahydro-1′,1′,4′,4′-tetramethyl-6′-naphthalenyl) acetate 2 and the corresponding acid 4 were prepared as intermediates in the synthesis of the retinoic acid receptor gamma-specific agonist ( R )-3-fluoro-4-[[hydroxy(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)acetyl]amino]benzoic acid 7 . Enantioselective reduction of ethyl 2-oxo-2-(1′,2′,3′,4′-tetrahydro-1′,1′,4′,4′-tetramethyl-6′naphthalenyl)acetate 1 to alcohol 2 was carried out using Aureobasidium pullulans SC 13849 in 98% yield and with an enantiomeric excess (e.e.) of 96%. Among microorganisms screened for the reduction of 2-oxo-2-(1′,2′,3′,4′-tetrahydro-1′,1′,4′,4′-tetramethyl-6′-naphthalenyl)acetic acid 3 to hydroxy acid 4 , Candida maltosa SC 16112 and two strains of Candida utilis (SC 13983, SC 13984) gave reaction yields of >53% with e.e.s of >96%.