Hemisynthesis and absolute configuration of novel 6-pentyl-2H-pyran-2-one derivatives from Trichoderma spp.

A comparative study of the secondary metabolism of two Trichoderma spp. with that of the Thctf1 transcription factor gene null mutant of Trichoderma harzianum 34 was carried out in order to deepen our knowledge of the biosynthetic pathway and mode of action of 6-pentyl-2H-pyran-2-one (1) and its derivatives as biocontrol agents. New isolated metabolites have shed light on the detoxification mechanism of 6-pentyl-pyranone by Trichoderma spp. All new compounds were synthesized and their stereoisomer characterized. The absolute configuration of 6-[(1′R,2′S)-dihydroxypentyl]-2H-pyran-2-one and 6-((1′S,2′R)-2′-propyloxiran-1-yl)-2H-pyran-2-one was determined by NMR analysis of the corresponding Mosher’s esters.