The contra-thermodynamic isomerization of α- and β-substituted cinnamate derivatives catalyzed by the Cu(OAc)2/rac-BINAP complex under blue light irradiation is reported. The use of an oxazolidinone template, which favored the complexation of the copper catalyst to the substrate, allowed the E → Z isomerization of the catalytically formed chromophore under simple and robust reaction conditions in good
Compounds of the formula: ##STR1## which are useful as anti-ulcer agent are provided.
提供了作为抗溃疡药物有用的化合物的公式:##STR1##
Stereoselective Iridium-N,P-Catalyzed Double Hydrogenation of Conjugated Enones to Saturated Alcohols
作者:Bram B. C. Peters、Jia Zheng、Suppachai Krajangsri、Pher G. Andersson
DOI:10.1021/jacs.2c02422
日期:2022.5.18
multitude of catalytic systems have been developed for this purpose. However, due to the different nature of the π-system, the hydrogenation of olefins and ketones is normally catalyzed by different metal complexes. Herein, a study on the effect of additives on the Ir-N,P-catalyzed hydrogenation of enones is described. The combination of benzamide and the development of a reactive catalyst unlocked a
Highly <i>E</i>-Selective Solvent-Free Horner-Wadsworth-Emmons Reaction for the Synthesis of α-Methyl-α,β-Unsaturated Esters Using Either LiOH·H<sub>2</sub>O or Ba(OH)<sub>2</sub>·8H<sub>2</sub>O
作者:Kaori Ando、Wakana Isomura、Nariaki Uchida、Kanae Mori
DOI:10.1246/bcsj.20220052
日期:2022.6.15
Horner-Wadsworth-Emmons reaction, which stirs a mixture of aldehyde, phosphonate reagent 1, and a base without solvent. The reaction of aromatic aldehydes and triethyl 2-phosphonopropionate 1a using LiOH·H2O gave 95-99% E-selectivity in 83-97% yield. The reaction of 1a with aliphaticaldehydes gave 92-94% E-selectivity except for α-branched aldehydes, and the selectivity was improved to 97-98% using ethyl 2-(diis
( E )-α-甲基-α,β-不饱和酯通过Horner-Wadsworth-Emmons 反应制备,该反应在无溶剂的情况下搅拌醛、膦酸酯试剂1和碱的混合物。芳香醛和 2-膦酰基丙酸三乙酯1a使用 LiOH·H 2 O 反应得到 95-99% E-选择性,产率为 83-97%。1a与脂肪醛的反应产生92-94% E-选择性,除了 α-支链醛,使用 2-(二异丙基膦酰基)丙酸乙酯1b将选择性提高到 97-98% 。使用 2-膦酰基丙酸三异丙酯1c改善了与 α-支链脂肪醛的反应和Ba(OH) 2 ·8H 2 O,得到98->99%的E-选择性和高产率。在THF中使用Ba(OH) 2 ·8H 2 O的HWE反应也以高产率高度选择性地得到( E )-α-甲基-α,β-不饱和酯。
Enantioselective Synthesis of α-Chiral Amides by Catalytic Hydrogenation with Iridium N,P-Complexes
作者:Bram B. C. Peters、Norman Birke、Pher G. Andersson、Luca Massaro
DOI:10.1055/s-0042-1751399
日期:——
The catalytic asymmetric hydrogenation of olefins constitutes a powerful method for the preparation of chiral compounds. A series of prochiral unsaturated amides were efficiently reduced with high enantioselectivities by means of an iridium N,P-complex-catalyzed hydrogenation. Its application in the synthesis of fenpropidin and the possibility of using isomeric mixtures of starting materials are attractive