RESUMO
A Rh-based catalytic system implying electron-poor MeOBIPHEP analogues has been developed for the 1,4-addition of boronic acids to maleimides and enones under mild conditions at room temperature and led to succinimide derivatives and arylated cyclic ketones in good to excellent yields and ee. We uncovered the crucial role of the electronic and steric properties of diphosphine ligand and observed a strong boronic acid/ligand dependency in the case of maleimide derivatives and substrate/ligand matching in the case of cyclic enones.
Assuntos
Derivados de Benzeno/química , Ácidos Borônicos/química , Maleimidas/química , Compostos Organofosforados/química , Ródio/química , Catálise , Técnicas de Química Combinatória , Ligantes , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Fosfinas/química , Estereoisomerismo , TemperaturaRESUMO
The Ir(III) complex [Ir(2)H(2)I(3)((rac)-Binap)(2)](+)I(-) efficiently promotes the selective dimerization of 1,6-, 1,7-enynes and functionalized alkynes. This catalytic process results in the formation of head-to-head isomers with (E)-stereoselectivity. Subsequent Rh-catalyzed cycloisomerization under reductive conditions led to the corresponding 1,2-dialkylidenecyclopentane derivatives.