An expeditious preparation of the 6-exo-hydroxybicyclo[2.2.2]octan-2-one ethylene dithioacetal 2b, a key intermediate in the synthesis of (þ)-13-stemarene (4) and (þ)-18-deoxystemarin (5) is described. Compound 2b was obtained as the major product by equilibrating the endo rich mixture of 6-hydroxybicyclo[2.2.2]octan-2-one ethylene dithioacetals 2 with TsOH in benzene at reflux, easily available from the corresponding hydroxy ketones 9. The model experiments which preceeded the above transformation, not previously described in the literature, are also presented.Introduction. By Raney-Ni desulfurization, hydroxydithioacetals 1 and 2b were in fact transformed into bicyclo[2.2.2]octan-2-ols 6 and 7, and the latter rearranged 3 ) to the stemarane system (Scheme 1).Compounds 1 and 2b were efficiently prepared from the corresponding 6-exohydroxybicyclo[2.2.2]octan-2-ones 8 and 9b by thioacetalization with 1,2-ethanedithiol in the presence of BF 3 · Et 2 O [2] [6]. Given that 6-exo-hydroxybicyclo[2.2.2]octan-2-ones of the type of 8 and 9b are the minor products (endo/exo 85 : 15) of the intramolecular aldol condensation of a 3-oxocyclohexaneacetaldehyde [7] [8] (Scheme 2), the efficiency of the synthesis of stemarane diterpenoids, by this approach,