Iridium-Catalyzed Highly Efficient and Site-Selective Deoxygenation of Alcohols
作者:Shiyi Yang、Weiping Tang、Zhanhui Yang、Jiaxi Xu
DOI:10.1021/acscatal.8b02495
日期:2018.10.5
An iridium-catalyzed, highly efficient, and site-selective deoxygenation of primary, secondary, and tertiary alcohols has been realized, under the assistance of a 4-(N-substituted amino)aryl directing group. Only the hydroxyl adjacent to the directing group can be deoxygenated. The deoxygenation is performed in water, with formic acid as both the promoter and hydride donor. Excellent yields and functionality
19F nuclear magnetic resonance studies of aromatic compounds. Part III. The transmission of substituent effects across bridged ring systems
作者:I. R. Ager、L. Phillips、S. J. Roberts
DOI:10.1039/p29720001988
日期:——
bridged dinuclear aromatic compounds of the type p-F·C6H4·Z·C6H4·X-p[Z = all-trans-·CHCH–CHCH·, CCH2, CH2, CH(OH), CMe(OH), –O–, or –S–; X = NH2, OMe, H, F, Cl, or NO2] is described. The 19F n.m.r. spectra of these compounds are used to examine the ‘transmission’ of electronic effects, due to the group X, across the bridge Z. A distinction is drawn between ‘transmission effects’ in which electron density
几个系列的类型的双核桥接的芳族化合物的合成中p -F·C 6 H ^ 4 ·Z·C 6 H ^ 4 ·X- p [Z =清一色反式- ·CH CH-CH CH·,C CH 2,CH 2,CH(OH),CMe(OH),– O–或–S–;描述了X = NH 2,OMe,H,F,Cl或NO 2 ]。在19这些化合物的F nmr光谱用于检查由于基团X跨桥Z引起的电子效应的“透射”。在“透射效应”之间进行了区分,其中电子密度可以认为是从一个相互影响和“继电器效应”,其中可能没有电子密度的净转移。
Palladium-catalyzed coupling reactions of (ArCH2)Ti(O-i-Pr)3 with aromatic or heteroaromatic bromides
Three benzyltitaniumcompounds of (ArCH2)Ti(O-i-Pr)3 (Ar = Ph (1a), 4-MeOC6H4 (1b), 4-FC6H4 (1c)) were prepared and used as benzyl nucleophiles for coupling reactions with aromatic or heteroaromatic bromides. The simple catalytic system of 1 mol % Pd(OAc)2 and 2 mol % PCy3 worked efficiently for a wide variety of aromatic bromides, producing diarylmethanes in good to excellent yields of up to 96%.
三种benzyltitanium的(ARCH化合物2)的Ti(O-我-Pr)3(Ar为Ph(上1A),4- MeOC 6 H ^ 4(1B),4-FC 6 H ^ 4(1C制备))中并用作苄基亲核试剂,用于与芳族或杂芳族溴化物偶联反应。1 mol%Pd(OAc)2和2 mol%PCy 3的简单催化系统可以有效地用于各种芳族溴化物,以高达96%的优异收率生产二芳基甲烷。受阻芳族溴化物或含有吸电子取代基的芳族溴化物的偶联反应在3-6小时的较长反应时间内较慢。溴吡啶,溴呋喃或溴噻吩的杂芳族溴化物与1a或1b的苄基试剂反应需要更长的反应时间12–24 h或更高的反应温度80°C,从而产生吡啶基,呋喃基和噻吩基-芳基甲烷中等产量。
The transmission power of a bridging mercury atom
作者:L. S. Golovchenko、S. I. Pombrik、A. S. Peregudov、D. N. Kravtsov