Asymmetric organocatalytic reduction of ketimines with catecholborane employing a N-triflyl phosphoramide Brønsted acid as catalyst
作者:Dieter Enders、Andreas Rembiak、Matthias Seppelt
DOI:10.1016/j.tetlet.2012.11.055
日期:2013.2
The first asymmetric reduction of ketimines with catecholborane employing an enantiopure N-triflyl phosphoramide as the organocatalyst has been developed. Five mole % of the catalyst provides the corresponding secondary amines in very good to almost quantitative yields and good enantioselectivities up to 86:14 e.r. under mild reaction conditions.
Cyclometalated Complexes of Ruthenium, Rhodium and Iridium as Catalysts for Transfer Hydrogenation of Ketones and Imines
作者:Nicolas Pannetier、Jean-Baptiste Sortais、Jean-Thomas Issenhuth、Laurent Barloy、Claude Sirlin、Alexandre Holuigue、Laurent Lefort、Lavinia Panella、Johannes G. de Vries、Michel Pfeffer
DOI:10.1002/adsc.201100152
日期:2011.10
[Ar(CO)R′′ in which R′′ is a tertiary alkyl group] the best catalyst was a ruthenium compound derived from bis[(R)-1-phenylethyl]amine, allowing the reduction of isobutyrophenone and cyclohexyl phenyl ketone which were both reduced with high enantioselectivities (ees up to 98%). This shows that the cyclometalated compounds have a high substrate specificity. In addition, acyclic and cyclic imines were reduced
Highly enantioselective transferhydrogenation of ketimines to the corresponding chiral amines was achieved with the chiral Ru(II) complex, prepared from the conformationally rigid and sterically bulky "roofed" cis-1,2-diamine.
We report the use of benzylamine as the amine component in Hantzsch ester mediated and chiral Bronsted acid catalyzed enantioselective reductiveaminations of ketones. The method is noteworthy because the benzyl group is easily removable, and amine product purification is achieved through Hantzsch ester oxidation product removal via basic hydrolysis.