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Peracetic acid oxidation a t -78 "C of the dihydroxybicyclo[3.2.0] heptan-6-one (23) afforded the dihydroxylactone (24) which was protected as its bisdimethyl-t-butylsilyl ether (26) and reduced to the corresponding lactol (27). A Wittig reaction on ( 27), carried out in benzene with a short reaction time, gave mainly the required 11 ccsilyl ether (28) together with a trace of the 9a-silyl ether (29) which results from 1,5-migration of the silyl group.Oxidation of (28) followed by quantitative deprotection using aqueous H F in acetonitrile afforded (f) methyl ester (20). This short stereo-and regio-selective total synthesis proceeds in an overall yield of 10% starting from cyclopentadiene.