Stereoselective synthesis of (E)-4-alkylidenecyclopent-2-en-1-ones by a tandem ring closure-Michael addition-elimination.
Reaction of (Z)-1,4-diketones with various functionalized nitroalkanes in the presence of DBU gives 4-alkylidenecyclopent-2-en-1-ones with E selectivity. A cyclopentadienone intermediate is probably formed by intramolecular aldol condensation, and this reacts with a nitroalkane giving a Michael addition-elimination.
Ballini
R
R
Dipartimento di Scienze Chimiche, Università di Camerino, via S. Agostino, 1. I-62032 Camerino, Italy.
Bosica
G
G
Fiorini
D
D
Gil
M V
MV
Petrini
M
M