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.