N-heterocyclic carbene catalysis promoted the unprecedented decarboxylative coupling of aryl aldehydes and tertiary or secondary alkyl carboxylic acid-derived redox-active esters to produce aryl alkyl ketones. The mild and transition-metal-free reaction conditions are attractive features of this method. The power of this protocol was demonstrated by the functionalization of pharmaceutical drugs and natural
Regio- and Chemoselective CH Chlorination/Bromination of Electron-Deficient Arenes by Weak Coordination and Study of Relative Directing-Group Abilities
作者:Xiuyun Sun、Gang Shan、Yonghui Sun、Yu Rao
DOI:10.1002/anie.201300176
日期:2013.4.15
It's all relative: A practical and efficient PdII‐catalyzed regio‐ and chemoselectivechlorination/bromination has been developed for the facile synthesis of a broad range of aromatic chlorides. The reaction demonstrates excellent reactivity, good functional‐group tolerance, and high yields. A preliminary study was conducted to evaluate relative directing‐group abilities of various functionalities
A novel protocol for ortho-C–H alkylation of aromatic and heteroaromatic ketones and esters under Cp*Co(III) catalysis has been developed for the first time. The reaction proceeds through initial cyclometalation via weak chelation-assisted C–H bond activation, followed by coordination of activated alkene, insertion between Co–C, and protodemetalation.
Pd-Catalyzed CH Oxygenation with TFA/TFAA: Expedient Access to Oxygen-Containing Heterocycles and Late-Stage Drug Modification
作者:Gang Shan、Xinglin Yang、Linlin Ma、Yu Rao
DOI:10.1002/anie.201207458
日期:2012.12.21
Acid brings the oxygen: A generalmethod for palladium‐catalyzed CH oxygenation has been developed for the facilesynthesis of a wide range of functionalized phenols with readily available aryl ketones, benzoates, benzamides, acetanilides, and sulfonamides. A trifluoroacetic acid/trifluoroacetic acid anhydride solvent system serves as the oxygen source and is the critical factor for CH activation
Substituent Effects. 22. The Solvolysis of α-<i>t</i>-Butylbenzyl Tosylates
作者:Yutaka Tsuji、Mizue Fujio、Yuho Tsuno
DOI:10.1246/bcsj.63.856
日期:1990.3
r values suggest the operation of the kc mechanism in this solvolysis without nucleophilic solvent assistance and methyl participation. From a comparison of the substituent effects, the exalted r value of 1.15 observed in the solvolysis of α-methylbenzyl chlorides can be attributed to the enhanced resonance demand characteristic of secondary benzylic system rather than to a correlational artifact arising