VITAMIN-B-12-CATALYZED C,C-BOND FORMATION - SYNTHESIS OF JASMONATES VIA SEQUENTIAL RADICAL REACTION

The Cbl-catalyzed electroreduction of 3-(2'-bromo-1'-ethoxyethoxy)cyclopenten (la) in presence of 1-cyanovinyl-acetate (8) gave, in a sequential radical reaction (5-exo-trig-cyclization of 1a followed by addition to 8), 1-cyano-2-(2'-ethoxy-hexahydro-2'H-cyclopenta[b]furan-4'-yl)ethyl acetate (10a). This intermediate was transformed to methyl jasmonate (7; four steps) and epituberolide (9; three steps) in 20 and 31% yield, respectively, from cyclopent-2-en-1-ol.