A rhodium-catalyzed hydroformylation of alkynes with formic acid was developed. The method provides α,β-unsaturated aldehydes in high yield and E-selectivity without the need to handle toxic CO gas.
1,4-Bis-Dipp/Mes-1,2,4-Triazolylidenes: Carbene Catalysts That Efficiently Overcome Steric Hindrance in the Redox Esterification of α- and β-Substituted α,β-Enals
作者:Veera Reddy Yatham、Wacharee Harnying、Darius Kootz、Jörg-M. Neudörfl、Nils E. Schlörer、Albrecht Berkessel
DOI:10.1021/jacs.5b11796
日期:2016.3.2
2,4-triazolium salts were synthesized and evaluated as (pre)catalysts in the redox esterification of various α- or β-substituted enals. In particular the 1,4-bis-Mes/Dipp-1,2,4-triazolylidenes overcome the above limitations and efficiently catalyze the redox esterification of a whole series of α/β-substituted enals hitherto not amenable to NHC-catalyzed transformations. The synthetic value of 1,4-bis-Mes/Dipp-1
Multicatalytic Stereoselective Synthesis of Highly Substituted Alkenes by Sequential Isomerization/Cross-Coupling Reactions
作者:Ciro Romano、Clément Mazet
DOI:10.1021/jacs.8b02134
日期:2018.4.4
patterns to deliver products with high control of the newly generated C═C bond. A highlyenantioselective variant of this [Ir/Ni] sequence has been established using a chiral iridium precatalyst. A complementary [Pd/Ni] catalytic sequence has been optimized for alkenyl methyl ethers with a remote C═C bond. The final alkenes were isolated with a lower level of stereocontrol. Upon proper choice of the Grignard
Aromatic dienoyl tetramic acids. Novel antibacterial agents with activity against anaerobes and staphylococci
作者:Terry Rosen、Prabhavathi B. Fernandes、Mary A. Marovich、Linus Shen、James Mao、Andre G. Pernet
DOI:10.1021/jm00125a022
日期:1989.5
Streptolydigin (1) and tirandamycin A (2) are typical members of the naturally occurring class of 3-dienoyltetramicacids. These compounds, which possess potent antibacterial activity particularly against anaerobes, have been shown to inhibit bacterial RNA polymerase. In contrast, tenuazonic acid (5), which lacks a complex dioxabicyclononane moiety and diene chromophore present in 1 and 2, exhibits
Synthesis of ?-cyclohexyl- and ?,?-alkylene-?,?-dicarbonyl-substituted dienes and study of their valence isomerization
作者:Zh. A. Krasnaya、V. S. Bogdanov、S. A. Burova、Yu. V. Smirnova
DOI:10.1007/bf00696716
日期:1995.11
ing α,β∶γ,δ-dienes. The structures of the reaction products were studied using1H NMR,13C NMR, and UV spectroscopy. The diene keto esters bearing no substituents at the γ-position were shown to be in fact three-component equilibrium mixtures comprised ofE- andZ-isomers of the diene (at the α,β bond) and a corresponding 2H-pyran. On the other hand, for keto esters with a Me group at the γ-position the
摘要 β-环己基丙烯醛、β-环己基异丁烯醛或α-环亚烷基链烷醛与乙酰乙酸甲酯或丙二酸二甲酯缩合得到δ-环己基-和δ,δ-亚烷基取代的α,α-二羰基α,β∶γ,δ-二烯。使用1H NMR、13C NMR和UV光谱研究了反应产物的结构。在γ-位不带取代基的二烯酮酯实际上是三组分平衡混合物,由二烯的E-和Z-异构体(在α,β键处)和相应的2H-吡喃组成。另一方面,对于在 γ 位具有 Me 基团的酮酯,平衡完全转移到 2H-吡喃。与酮酯相反,二烯二酯仅以开放形式存在。