Stereocontrolled approach to highly substituted cyclopentanones. Application in a formal synthesis of Δ(9(12))-capnellene

Article abstract of DOI:10.1016/S0040-4020(97)10387-8

A direct stereocontrolled route for the construction of highly substituted cyclopentanones 10a-d has been developed starting from acyclic ketones 5a,b. The key step involves copper(I)-catalysed stereoselective photocycloaddition of the dienes 6a-d followed by stereospecific rearrangement of the cyclobutane derivatives 7a,b, 8 and 9. Employing this methodology a formal synthesis of the sesquiterpene Δ(9(12))-capnellene 2 has been achieved.