Stereoselective Formation of Metabolites from 2-Methyl-2-hepten-6-one by Botrytis cinerea.

Abstract Controlled conversion of 2-methyl-2-hepten-6-one ( 1 ) by Botrytis cinerea resulted in the formation of ( S )-(+)-2-methyl-2-hepten-6-ol (sulcatol) ( 2 ) of 90% ee. In addition, (2 R , 5 R )- ( 3a ), (2 S ,5 S )- ( 3a′ ), (2 R ,5 S )- ( 3b ) and (2 S ,5 R )-2-(1-hydroxy-1-methylethyl )-5-methyltetrahydrofuran ( 3b′ ), (3 s , 6 R )- ( 4a ), (3 R ,6 S )- ( 4a′ ), (3 R ,6 R )- ( 4b ) and (3 S ,6 S )-tetrahydro-2,2,6-trimethyl-2 H -pyran-3-ol ( 4b′ ) as well as the diastereomeric dihydro-3-hydroxy-5-methyl-5-(2′-methyl-pent-2-en-5′-yl)-2(3 H )-furanones ( 5a/b ) were found as biotransformations products of 1 . Chiral analysis carried out by on-line multidimensional gas chromatography-mass spectrometry (MDGC-MS) revealed the following ee values: 46 % ( 3a ); 80 % ( 3b ); 56 % ( 4a ); and 60 % ( 4b′ ). As confirmed by nOe experiments, 5a/b were formed in a ratio of 6:1.