Regio- and stereoselective hydroxylation of bi- and tricyclic enones by fungal strain Fusarium culmorum

Abstract

The strain of Fusarium culmorum AM282 was used to investigate hydroxylation of both enantiomers of 4a-methyl hexahydronaphtalenone and a related sesquiterpenoid enone: (1 S)-1,4,4-trimethyltricyclo[5.4.0.0 3,5]undec-7-en-9-one. It was found that the position and stereochemistry of the introduced hydroxyl group depended on the structure of a substrate. The S-enantiomer of 4a-methyl-hexahydronaphtalenone was hydroxylated exclusively at the allylic, 8 R-axial position, whereas the R-enantiomer mainly at the non-activated 6 S-equatorial position (the mixture of (6 S) and (8 S) hydroxy derivatives in 6:1 ratio was formed). Tricyclic, sesquiterpenoid derivative of R-hexahydronaphtalenone was hydroxylated at the unique 11 S-equatorial position. In a simple reaction, new hydroxylated chiral synthons: trans-(4a S,6 S)-4,4a,5,6,7,8-hexahydro-6-hydroxy-4a-methyl-2(3 H)-naphthalenone and (1 S,11 S)-11-hydroxy-1,4,4-trimethyltricyclo[5.4.0.0 3,5]undec-7-en-9-one were prepared.