Synthese makrocyclischer Ketone durch Ringerweiterung; ein neuer Weg zu$(\pm)$-Muscon

Abstract

Synthesis of Macrocyclic Ketones by Ring-Enlargement Reactions; a New Path to (+)-Muscone A new synthetic route to macrocyclic ketones is described. Starting from 2-nitrocycloalkanones, the ring-enlarged compounds of the type 4 and 5 were prepared in three steps. Reduction of the NOz group with Bu,SnH and azobisisobutyronitrile led in moderate yields to simple 8-keto-esters which were quantitatively hydrolyzed and decarboxylated to the ketones of the type 8 and 9. The interesting fragrances Exdfone@ @a) and (+)-muscone (9a) were prepared in this way in overall yields of 22 and 18 %, respectively.