Dimethylzinc-Mediated, Oxidatively Promoted Reformatsky Reaction of Ethyl Iodoacetate with Aldehydes and Ketones
作者:Pier Giorgio Cozzi、Alessandro Mignogna、Paola Vicennati
DOI:10.1002/adsc.200700572
日期:2008.5.5
A practical and general Reformatskyreaction, promoted by oxidants and mediated by dimethylzinc, is described. The reaction is fast and runs at 0 °C with aldehydes and ketones, under mild reaction conditions. Preliminary results obtained for the enantioselective version show that inexpensive chiral amino alcohols could be used in the challenging formation of enantioenriched quaternary stereogenic centers
d-Phg-l-Pro Dipeptide-derived prolinol ligands for highly enantioselective Reformatsky reactions
作者:Eun-kyoung Shin、Hyun Jung Kim、Yongtai Kim、Yangmee Kim、Yong Sun Park
DOI:10.1016/j.tetlet.2006.01.070
日期:2006.3
prepared from the dynamic kineticresolution of N-(α-bromo-α-phenylacetyl) proline ester 1 in asymmetric nucleophilic substitution and subsequent reduction. The peptide-derived prolinols are tested as chiral ligands in the asymmetric addition of Reformatsky reagent to aromatic aldehydes. Chiral ligand 3c has been shown to be effective to produce enantioenriched β-hydroxyesters 5a–j with up to 98% ee
The development of new approaches to obtain optically pure β-hydroxy esters is an important area in synthetic organic chemistry since they are precursors of other high value compounds. Herein, the kineticresolution of racemic β-hydroxy esters using a planar-chiralDMAPderivative catalyst is presented. Following this procedure, a range of aromatic β-hydroxy esters was obtained in excellent selectivities
Planar Chiral Cyclic (Amino)(ferrocenyl)carbene as Ligand for Transition Metals
作者:Risa Yasue、Masaru Miyauchi、Kazuhiro Yoshida
DOI:10.1002/adsc.201600999
日期:2017.1.19
Planar chiral ferrocene‐fused iminium salts were synthesized in enantiomerically pure form. The novel planar chiral cyclic (amino)(ferrocenyl)carbene successfully generated from such salt was subjected to carbene trapping experiments with sulfur and copper chloride. The utility of the carbene as a chiral ligand for transition metals was preliminarily demonstrated in the copper‐catalyzed enantioselective
Application of Bidentate Oxazoline–Carbene Ligands with Planar and Central Chirality in Asymmetric β-Boration of α,β-Unsaturated Esters
作者:Zonghong Niu、Jianqiang Chen、Zhen Chen、Manyuan Ma、Chun Song、Yudao Ma
DOI:10.1021/jo5021135
日期:2015.1.2
oxazoline-substituted imidazolium salts based on [2.2]paracyclophane were synthesized and characterized. The new bidentate oxazoline–carbene precursor with planar and central chirality had significant advantage than the bicyclic 1,2,4-triazolium salt derived from [2.2]paracyclophane as a monodentate carbene ligand in Cu(I)-catalyzedasymmetric β-boration of α,β-unsaturated esters, giving the desired products