New monodentate chiral phosphite ligands for asymmetric hydrogenation
作者:Peter Hannen、H.-Christian Militzer、Erasmus M. Vogl、Florian A. Rampf
DOI:10.1039/b306793a
日期:——
We report the synthesis of new chiral monodentate phosphite ligands with a biphenyl backbone, the axial chirality of which is introduced early in the synthesis and locked by a chiral alkylenedioxy bridge. We also describe results obtained with these ligands in rhodium-catalysed asymmetric hydrogenation of various substrates.
Barium-catalyzed direct Mannich-type reactions of a beta,gamma-unsaturated ester are described. The Ba-catalyst not only promoted the Mannich-type reactions, but also isomerizedMannich adducts to afford beta-methyl aza-Morita-Baylis-Hillman-type products in 61-88% yield from various aryl, heteroaryl, and alkyl imines. Preliminary trials on enantioselective variants with a chiral biaryldiol ligand
Installing Stable Molecular Chirality within the Walls of Periodic Mesoporous Organosilicas via Self-Assembly
作者:Lacey M. Reid、Cathleen M. Crudden
DOI:10.1021/acs.chemmater.6b02153
日期:2016.11.8
The synthesis of highly ordered chiralperiodic mesoporous organosilica (PMO) materials is described using a novel approach. Chiral dopants featuring removable chirality were combined with freely rotating bulk monomers, resulting in a bulk chiralmaterial with handedness related to the chiral dopant. Once incorporated into the PMO, removal of the chiral-linker in the dopant is readily accomplished
Asymmetric Desymmetrization of 2,2‘,6,6‘-Tetrahydroxybiphenyl through Annulation with Enantiomerically Pure Bis(mesylate)
作者:Toshiro Harada、T. Mai T. Tuyet、Akira Oku
DOI:10.1021/ol0057840
日期:2000.5.1
2,2',6,6'-Tetrahydroxybiphenyl undergoes a facile annulation reaction with bis(mesylate) derived from (S)-1,2-propanediol in the presence of Cs2CO3 to give the corresponding asymmetric desymmetrization product of S axial chirality with exclusive diastereoselectivity. The desymmetrization product can be utilized as a versatile chiral building block in asymmetric synthesis of axially chiral 6,6'-disubstituted 2,2'-biphenyldiols.