66. β-Cleavage of Potassium bicyclooct-5-en-2-olates. Stereoselective Synthesis of (+-)-Trichodiene

Article abstract of DOI:10.1002/hlca.19890720318

The transformation 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 I).As an illustration of this synthetic methodology, a stereoselective synthesis of (+)-trichodiene ((+)-1) is described wich involves the β-cleavage of the tricyclic potassium alkoxides 46a and 47a to cyclopentanone 4 (cf.Scheme 7).