Superacidic cyclisation–lipase-mediated kinetic resolution as a short route from achiral linear isoprenoid alcohols to scalemic cyclic isomers

(±)-α-Cyclogeraniol and (±)-drim-7-en-11-ol acetates obtained via the FSO₃H-induced cyclisation of geraniol and (E)-farnesol and subsequent acetylation were hydrolysed in the presence of hog pancreas lipase (PPL) to afford (R)-(+)-α-cyclogeraniol (ee ∼30% at the optimal conversion C = 20±2%) and (5R,9R,10R)-(+)-drim-7-en-11-ol (ee 78.5% at C = 30%), respectively; (±)-15-acetoxyisoagath-12-ene, obtained similarly from all-E-geranylgeraniol, is resistant to PPL-mediated hydrolysis, but is hydrolysed in the presence of lipase from Candida cylindracea to afford (10S,14R)-(−)-isoagath-12-en-15-ol of 69–80% ee in ∼3% yield.