One-Pot Synthesis of Unsymmetrical Benzils by Oxidative Coupling Using Selenium Dioxide and p-Toluenesulfonic Acid Monohydrate
作者:Md. Rumum Rohman、Icydora Kharkongor、Mantu Rajbangshi、Hormi Mecadon、Badaker M. Laloo、Priti R. Sahu、Iadeishisha Kharbangar、Bekington Myrboh
DOI:10.1002/ejoc.201101012
日期:2012.1
The oxidative coupling of the α-carbon atom of aromatic ketones with unactivated arenes in the presence of seleniumdioxide and p-toluenesulfonic acid monohydrate is described. A number of unsymmetrical benzils have been prepared in good yields (38–75 %) with high regioselectivity. The generality and functional tolerance of this new protocol is demonstrated. The mechanistic pathway for the oxidative
reductive coupling reaction was established for the synthesis of diaryl 1,2-dicarbonyl compounds from arylmethyl ketones in good yields. The mechanisticstudy showed the reaction undergoes C(CO)–C(sp3) bond cleavage, with the reductive coupling reaction occurring through an electron transfer process. Notably, the reaction not only is simple to operate but also has mild reaction conditions and a wide
Synthesis of unsymmetrical benzils using N-heterocyclic carbene catalysis
作者:Yumiko Suzuki、Abu Bakar、Takashi Tanoi、Naoko Nomura、Masayuki Sato
DOI:10.1016/j.tet.2011.04.020
日期:2011.6
In this paper, we propose a novel and efficient method for the preparation of various unsymmetricalbenzils. We first demonstrate the nucleophilic aroylation of N-phenylbenzimidoyl chlorides with aromatic aldehydes using N-heterocyclic carbene as the catalyst to afford 1-aryl-2-phenyl-2-(phenylimino)ethanones. These iminoethanones were then converted to 1,2-diaryl-1,2-diketones by acid-promoted hydrolysis
Novel regioselective hydrodeoxygenation of α-diketones with phosphites as the deoxygenation reagent was realized via visible-light photoredox catalysis. Broad substrate scope and high functional group compatibility were obtained. Unsymmetric α-diketones were selectively reduced at the carbonyls of higher electrophilicity. This unique regioselectivity compared with available methods makes it a practical