Facile Ramberg–Bäcklund reactions for the synthesis of 2,3-disubstituted cyclopentenones; a short synthetic route to tetrahydrodicranenone B

Abstract

The Ramberg–Bäcklund reaction has been employed to prepare protected 2,3-disubstituted cyclopent-3-enones which have been converted into cyclopent-3- and -2-enones; the α-iodosulphone precursors were obtained by a double Michael approach using a three-component coupling sequence to introduce the alkyl substituents and this methodology has been used to develop a short synthetic route to the antimicrobial natural product, tetrahydrodicranenone B (1).