The role of attractive van der Waals forces in the catalysis of Michael addition by a phenyl decorated uranyl-salophen complex.
The Et(3)N-assisted addition of beta-ketoester 3 to MVK in chloroform is catalyzed with high turnover efficiency by the phenyl-substituted uranyl-salophen compound 2b but not by the parent compound 1b. A plausible mechanism is suggested, involving concomitant nucleophilic attack at the beta-carbon and hydrogen bonding between the Et(3)NH(+) countercation and the carbonyl oxygen of the s-cis conformation of the enone reactant. The role of the van der Waals interactions with the aromatic side arm of 2b as a crucial driving force for catalysis is discussed.
Dalla Cort
Antonella
A
Dipartimento di Chimica and IMC-CNR Sezione Meccanismi di Reazione, Università La Sapienza, Box 34 Roma 62, 00185 Roma, Italy.
Mandolini
Luigi
L
Schiaffino
Luca
L