highly efficient hydroesterification of alkynesemployingarylformates has been developed without the use of externalcarbonmonoxide and at ambient pressure. The reaction in the presence of a palladium-xantphos catalyst system selectively affords α,β-unsaturated esters in good to high yields. Use of an aryl formate is crucial and alkyl formates did not react at all. The hydroesterification of norbornene
Silver-Catalyzed Cross-Olefination of Donor and Acceptor Diazo Compounds: Use of<i>N</i>-Nosylhydrazones as Diazo Surrogate
作者:Zhaohong Liu、Binbin Liu、Xue-Feng Zhao、Yan-Bo Wu、Xihe Bi
DOI:10.1002/ejoc.201601610
日期:2017.1.26
The cross-olefination reaction of donor and acceptor diazocompounds is reported. The use of N-nosylhydrazones as the diazo surrogates and the dependence on silver catalysis are crucial for the reaction development. A variety of (hetero)aryl N-nosylhydrazones and α-diazo esters, amides, and phosphonates were compatible, affording functionalized alkenes in good-to-high yields with moderate Z/E selectivity
Lipophilic NHC catalysis in aqueous medium was reported for the synthesis of biologically relevant (a)symmetrically substituted and unsymmetrically substituted syncarpamide analogues. All the reported reactions were performed in the absence of any expensive metal salts or additives. A diverse array of syncarpamide analogues was obtained in good yields. Lipophilic NHC catalysis was also extended to
Dinuclear Zinc Catalyzed Asymmetric Spirannulation Reaction: An Umpolung Strategy for Formation of α-Alkylated-α-Hydroxyoxindoles
作者:Barry M. Trost、Keiichi Hirano
DOI:10.1021/ol300577y
日期:2012.5.18
A highlydiastereo- and enantioselective formal [3 + 2] cycloaddition of α,β-unsaturated esters and 3-hydroxyoxindoles catalyzed by a dinuclear zinc-ProPhenol complex is reported. The stereoselective Michaeladditions of 3-hydroxyoxindoles and the subsequent transesterifications afford spirocyclic δ-lactones.
Axially dissymmetric binaphthyldiimine chiral salen-type ligands for copper-catalyzed asymmetric aziridination
作者:Min Shi、Chuan-Jiang Wang、Albert S.C. Chan
DOI:10.1016/s0957-4166(01)00534-1
日期:2001.12
chiral salen-type ligands 1–4 and 7 were prepared from the reaction of (R)-(+)-1,1′-binaphthyl-2,2′-diamine with 2,6-dichlorobenzaldehyde, 2,3-dichlorobenzaldehyde, 3,4-dichlorobenzaldehyde or salicylaldehyde in high yields, respectively. The catalytic asymmetricaziridination of alkenes has been examined using these novel chiral ligands. Excellent enantioselectivity in the aziridination of cinnamates