Raising the HOMO: 2,4‐Dienals can react with nitroalkenes in trienamine‐catalyzed asymmetricDiels–Alderreactions (see scheme). Crucial for the success is raising the HOMO energy of the diene through the introduction of appropriate substituents. The reaction exhibits unusually high enantioselectivity and exo selectivity; endo addition is possibly disfavored because of the electrostatic repulsion shown
[EN] HYDROGENATION OF DIENALS WITH RHODIUM COMPLEXES UNDER CARBON MONOXIDE FREE ATMOSPHERE<br/>[FR] HYDROGÉNATION DE DIÉNALS AU MOYEN DE COMPLEXES DE RHODIUM SOUS UNE ATMOSPHÈRE EXEMPTE DE MONOXYDE DE CARBONE
申请人:FIRMENICH & CIE
公开号:WO2012150053A1
公开(公告)日:2012-11-08
The present invention relates to the field of catalytic hydrogenation and, more particularly, to a process for the reduction by hydrogenation, using molecular H2, of a C6-C20 conjugated dienal into the corresponding deconjugated enal, characterized in that said process is carried out in the presence of a catalytic system comprising at least a base and at least one complex in the form of a rhodium complex comprising a C34-C60 bidentate diphosphine ligand (L2) coordinating the rhodium.
A synthetic process merging oxidativedearomatization and asymmetric aminocatalysis in a single vessel is reported. The PhI(OAc)2-mediated oxidation of 1,4-dihydroxynaphthalene is followed by a trienamine-mediated Diels–Alder cycloaddition/aldol reaction or a trienamine-mediated Diels–Alder cycloaddition/oxidation sequence depending on the dienal substitution pattern. The polycyclic compounds are obtained