1,4-Addition of N,N-Disubstituted Phenylacetamides to 2-Arylmethylene-1,4-butanolides
作者:Tzvetanka P. Cholakova、Alexander A. Dobrev、Assen B. Kanchev、Petja P. Mikhailova
DOI:10.1039/a904005f
日期:——
The 1,4-addition reaction of lithium derivatives of N,N-disubstitutedphenylacetamides with 2-arylmethylene-1,4-butanolides gives the corresponding N,N-disubstituted 2-(1-aryl-2-carbamoyl-2-phenylethyl)-1,4-butanolides 3a–f as diastereoisomeric mixtures with 40–68% yields.
The Migration of Double Bond under the Neutral Conditions. The Transformation of α-Alkylidene Cyclic Carbonyl Compounds to α,β-Unsaturated Cyclic Carbonyl Compounds
transformation of α-alkylidene cyclic carbonyl compounds to α,β-unsaturated cyclic carbonyl compounds was achieved. In the presence of catalytic amount of triethylsilane, tris(triphenylphosphine)rhodiumchloride was found to affect the migration of double bonds. Because of the neutral nature of reaction medium, the reaction proceeded in a clean manner without side reactions.
Regioselective Borohydride and Grignard Reactions in (<i>E</i>)-3-(Arylmethylene)-2-oxotetrahydrofurans
作者:Dibyendu De、Manju Seth、Amiya Prasad Bhaduri
DOI:10.1055/s-1990-27064
日期:——
Convenient syntheses of (E)-2-(arylmethylene)-1,4-butanediols 2a-c, 2-(aryl)-3-methylenetetrahydrofurans 4a,c, 3-(arylmethylene) -2-methyl-2,5-pentanediols 7a-c, 4-(arylmethylene)-3-ethyl- 3,6-hexanediols 7d-f, 2,2-dialky1-3-(arylmethylene)tetrahydrofurans 9a-f and 2,2-dialkyl-3-(arylmethyl)tetrahydrofurans 10a-b,10d-e are described. The synthetic utility of the title compounds is obvious from the ease of preparation of these new type of tetrahydrofuran derivatives.
P-Stereogenic Ir-MaxPHOX: A Step toward Privileged Catalysts for Asymmetric Hydrogenation of Nonchelating Olefins
作者:Maria Biosca、Pol de la Cruz-Sánchez、Jorge Faiges、Jèssica Margalef、Ernest Salomó、Antoni Riera、Xavier Verdaguer、Joan Ferré、Feliu Maseras、Maria Besora、Oscar Pàmies、Montserrat Diéguez
DOI:10.1021/acscatal.2c05579
日期:2023.3.3
The Ir-MaxPHOX-type catalysts demonstrated high catalytic performance in the hydrogenation of a wide range of nonchelating olefins with different geometries, substitution patterns, and degrees of functionalization. These air-stable and readily available catalysts have been successfully applied in the asymmetrichydrogenation of di-, tri-, and tetrasubstitutedolefins (ee′s up to 99%). The combination
Ir-MaxPHOX 型催化剂在各种具有不同几何形状、取代模式和功能化程度的非螯合烯烃的加氢中表现出高催化性能。这些空气稳定且易于获得的催化剂已成功应用于二、三和四取代烯烃(ee 高达 99%)的不对称氢化。理论计算和氘标记实验相结合,揭示了导致反应中观察到的对映选择性的因素,从而使这些 Ir 催化剂的最合适底物合理化。
Cross-Metathesis between α-Methylene-γ-butyrolactone and Olefins: A Dramatic Additive Effect
作者:Joëlle Moïse、Stellios Arseniyadis、Janine Cossy
DOI:10.1021/ol0703940
日期:2007.4.1
Olefin cross-metathesis between alpha-methylene-gamma-butyrolactone and terminal olefins is described. Moderate to excellent yields of alpha-alkylidene-gamma-butyrolactones were obtained with high E-stereoselectivity in the presence of low catalyst loading in refluxing CH2Cl2. In addition, the use of various additives was found to have a dramatic effect on the efficiency of the cross-metathesis (CM) process by circumventing the formation of the isomerized byproduct.