Enantioselective Synthesis of (-)-(7aS)-2,3,7,7a-Tetrahydro-7a-phenylthio-1H-indene-1,5(6H)-dione and (+)-(8aS)-3,4,8,8a-Tetrahydro-8a-phenylthio-1,6(2H,7H)-naphthalenedione

Article abstract of DOI:10.1055/s-1989-27400

Application of the Hajos-Parrish asymmetrically biased aldol condensation to 2-(3-oxobutyl)-2-phenylthio-1,3-cyclopentanedione (5a) or 2-(3-oxobutyl)-2-phenylthio-1,3-cyclohexanedione (5b) using (R)-(+)-proline provided (-)-(7aS)-2,3,7,7a-tetrahydro-7a-phenylthio-1H-indene-1,5(6H)-dione (7a) and (+)-(8aS)-3,4,8,8a-tetrahydro-8a-phenylthio-1,6(2H,7H)-naphthalenedione (7b), respectively, in >/= 95percent enantiomeric excess, as determined by 1H-NMR analysis using tris<3-heptafluoropropylhydroxymethylene)-(+)-camphorato>europium(III).