the amine nitrogen atom were prepared and evaluated in the asymmetrictransfer hydrogenation of ketones. Bidentate and tridentate ligands demonstrated a mutual exclusivity directly related to their function as catalysts. A broad series of ketones were reduced with these new catalysts, permitting the ready identification of an optimal catalyst for each substrate and revealing the subtle effects that changes
Intramolecular Triplet Energy Transfer in Flexible Molecules: Electronic, Dynamic, and Structural Aspects
作者:Peter J. Wagner、Petr Klán
DOI:10.1021/ja990224l
日期:1999.10.1
Exothermic intramolecular triplet energy transfer (TET) rate constants in various flexible bichromophoric systems D-(CH2)n-O-A (D = benzoyl, 4-methylbenzoyl; A = 2-naphthyl, 4-, 3-, 2-biphenyl; n = 3−14) have been determined from steady-state quenching and quantum yield measurements. The magnitude of the rate constants in molecules where n = 3 is comparable to those in molecules with a rigid spacer between
Nickel-Catalyzed Highly Selective Reductive Carbonylation Using Oxalyl Chloride as the Carbonyl Source
作者:Jiannan Wang、Yuqing Yin、Xiaoqian He、Qiao-Lian Duan、Ruopeng Bai、Hai-Wei Shi、Renyi Shi
DOI:10.1021/acscatal.3c01090
日期:2023.6.16
available chemical, is one of the most versatile organic reagents used in chemical reactions. In this work, high chemoselectivity can be achieved with a 1:1:1 ratio of Ar–I to alkyl-I to oxalyl chloride. A wide range of alkyl aryl ketones which present an important class of molecules in synthetic and medicinal chemistry are accessed from alkyl halides, aryl iodides, under mild conditions. Primary and secondary
An efficient cross-coupling between acylzirconocenes, readily prepared by hydrozirconation/carbonylation of alkenes, and diaryliodonium tetrafluoroborates is reported. This procedure enables the synthesis of a variety of alkyl-aryl-ketones upon simple catalysis with copper cyanide without the need of additional ligands and only requires a low pressure of carbon monoxide generated in situ, in a two-chamber