SYNTHESES OF 2-ETHYL-8-METHYL-1,7-DIOXASPIRO[5.5]UNDECANOLS

Synthetic approaches to ring- and side-chain hydroxy derivatives of th e 2-ethyl-8-methyl-1,7-dioxaspiro-[5.5]undecane system 8 are described . Alkylation reactions of diethyl 3-oxopentanedioate, pentane-2,4-dion e and acetone N,N-dimethylhydrazone have been employed. Appropriate ch oices of enantiomeric iodides in the alkylation sequences, sometimes f ollowed by asymmetric dihydroxylation of derived hydroxyenones, have p ermitted access to key enantiomers of these alcohols, which have been fully characterised by H-1 and C-13 NMR spectroscopy, gas chromatograp hic-mass spectrometric methods, and chiral gas chromatography.