Ruthenium-catalyzed [2 + 2 + 1] cocyclization of isocyanates, alkynes, and CO enables the rapid synthesis of polysubstituted maleimides.
Intermolecular [2 + 2 + 1] cocyclization of isocyanates, alkynes, and CO (1 atm) proceeded smoothly in the presence of a catalytic amount of Ru3(CO)12 (3.3 mol %) in mesitylene at 130 degrees C for 3 approximately 42 h to give a variety of polysubstituted maleimides in excellent yields with high selectivity. The reaction may involve an azaruthenacyclopentenone intermediate derived from oxidative cyclization of an isocyanate and an alkyne on an active ruthenium species.
Kondo
Teruyuki
T
Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan. teruyuki@sci.kyoto-u.ac.jp
Nomura
Masato
M
Ura
Yasuyuki
Y
Wada
Kenji
K
Mitsudo
Take-aki
TA