Identification of 2,3-dihydro-gamma-ionylideneethanol in Cercospora cruenta

During oar scrutiny of GC-EI-XIS date for C-15 alcohols as putative interme diates on the ABA biosynthetic pathway in Cercospora cruenta, a trace amoun t of 5-[2 ' ,2 ' -dimethyl-6 ' -methylene-1 ' -cycloltexyl]-3-methyl -4-pen ten-1-ol (2,3-dihgdro-gamma -ionylideneethanol) was identified. Feeding exp eriments indicated that this compound was not an intermediate to ABA, but a catabolite that originated from gamma -ionylideneacetaldehyde. The stereoc hemistry of 2,3-dihydro-gamma -ionylideneethanol was deduced to be (3R,1 'S ) from a comparison with an authentic specimen prepared via baker's yeast a symmetric reduction.