Asymmetric Catalysis with a Mechanically Point-Chiral Rotaxane
作者:Yusuf Cakmak、Sundus Erbas-Cakmak、David A. Leigh
DOI:10.1021/jacs.6b00303
日期:2016.2.17
Mechanical point-chirality in a [2]rotaxane is utilized for asymmetriccatalysis. Stable enantiomers of the rotaxane result from a bulky group in the middle of the thread preventing a benzylic amide macrocycle shuttling between different sides of a prochiral center, creating point chirality in the vicinity of a secondary amine group. The resulting mechanochirogenesis delivers enantioselective organocatalysis
The asymmetricα-amination of aldehydes was performed using a resin-supportedpeptidecatalyst. A tri- or tetrapeptide with an N-terminal D-Pro-Aib sequence efficiently catalyzed the reaction in a highly enantioselective manner. The supported catalyst could be easily recovered by filtration and reused at least ten times.
Polymer-immobilized α,α-bis[bis-3,5-(trifluoromethyl)phenyl]prolinol silyl ether: synthesis and application in the asymmetric α-amination of aldehydes
作者:Anton A. Guryev、Maksim V. Anokhin、Alexei D. Averin、Irina P. Beletskaya
DOI:10.1016/j.mencom.2015.11.002
日期:2015.11
alpha,alpha-Bis[bis-3,5-(trifluoromethyl)phenyl]prolinol silyl ether anchored onto polystyrene was synthesized and tested in asymmetric alpha-amination of aldehydes. The catalytic activity and enantioselectivity of the immobilized catalyst persist for 3 cycles.
An octahedral bis-cyclometalated iridium(III) complex catalyzes the enantioselective α-amination of aldehydes with catalyst loadings down to 0.1 mol%. In this metal-templated design, the metal serves as a structural center and provides the exclusive source of chirality, whereas the catalysis is mediated through the organic ligand sphere.