Abstract The transformations of 12 bicyclo [2.2. 2] oct-5-en-2-ols (V or VI) to 3-(cyclohex-3- enyl)-2-alkanones (III or IV), via β-cleavage of their potassium alkoxides in HMPA, has been investigated (cf. Table 1). As an illustration of this synthetic methodology, a stereoselective synthesis of (±)-trichodiene ((±)-1) is described which involves the β-cleavage of the tricyclic potassium alkoxides 46a and 47a to cyclopentanone 4 (cf. Scheme 7).