Chiral <i>C</i><sub>2</sub>-Symmetric Ligands with 1,4-Dioxane Backbone Derived from Tartrates: Syntheses and Applications in Asymmetric Hydrogenation
作者:Wenge Li、Jason P. Waldkirch、Xumu Zhang
DOI:10.1021/jo020250t
日期:2002.11.1
Chiral 1,4-diphenylphosphines 5-7 as well as thioether 8 were synthesized from tartrates employing Ley's "BDA" and "Dispoke" methodologies as the key step. Rhodium(I) complexes with 5-7 are efficient catalysts for the asymmetrichydrogenation of beta-substituted enamides and MOM-protected beta-hydroxyl enamides, which furnished chiral amines or beta-amino alcohols with 94-->99% ee. These results indicated
Synthesis of novel chiral binaphthyl phosphorus ligands and their applications in Rh-catalyzed asymmetric hydrogenation
作者:Yongxiang Chi、Xumu Zhang
DOI:10.1016/s0040-4039(02)00877-8
日期:2002.7
A series of new chiral mono- or bidentate phosphorus ligands were efficiently prepared through a key intermediate (S)-4-chloro-4,5-dihydro-3H-4-phosphacyclohepta[2,1-a;3,4-a′]binaphthalene and its derivatives. These ligands were applied in the Rh-catalyzedasymmetrichydrogenation of α-dehydro amino acids, enol acetates, itaconates, and enamides. Good to excellent enantioselectivities were obtained
通过关键中间体(S)-4-氯-4,5-二氢-3 H -4-磷酸环庚七[2,1- a ; 3,4- a ']双萘及其衍生物。这些配体用于α-脱氢氨基酸,烯醇乙酸酯,衣康酸酯和烯酰胺的Rh催化的不对称氢化。获得良好至优异的对映选择性(高达99.5%ee)。
Synthesis of a Novel Chiral Binaphthyl Phospholane and Its Application in the Highly Enantioselective Hydrogenation of Enamides
作者:Dengming Xiao、Zhaoguo Zhang、Xumu Zhang
DOI:10.1021/ol991074m
日期:1999.11.1
enantiomerically pure binaphthanol. This ligand possesses both binaphthyl chirality and phospholane functionality. Excellent enantioselectivities (95-99.6% ee) have been observed in hydrogenation of an isomeric mixture of (E)- and (Z)-beta-substituted-alpha-arylenamides by using a Rh-binaphane catalyst. These enantioselectivities are the highest reported to date for this transformation.
Synthesis of 3, 4-<i>O</i>-Isopropylidene- (3<i>S</i>,4<i>S</i>)-dihydroxy-(2<i>R</i>,5<i>R</i>)- bis(diphenylphosphino)hexane and Its Application in Rh-Catalyzed Highly Enantioselective Hydrogenation of Enamides
作者:Wenge Li、Xumu Zhang
DOI:10.1021/jo0004613
日期:2000.9.1
A Chiral 1,2-Bisphospholane Ligand with a Novel Structural Motif: Applications in Highly Enantioselective Rh-Catalyzed Hydrogenations