Synthesis and spectroscopic analysis of a stereoisomer library of the phytophthora mating hormone α1 and derived bis-Mosher esters.

Fluorous mixture synthesis provided all eight diastereomers of the phytophthora hormone α1 with the R configuration at C11 as individual samples after demixing and detagging. The library of all possible bis-Mosher esters (16) was then made by esterification. Complete sets of (1)H, (13)C, and (for the Mosher esters) (19)F NMR spectra were recorded, assigned, and compared with each other and with published spectra. Not all of the spectra are unique, and the (1)H NMR spectra of the Mosher esters provided the most information. The previous assignment of the natural sample as an "all-R" stereoisomer mixed with its 3S-epimer was confirmed.