A convenient synthetic method was reported for the preparation of N-phthaloyl dehydroamino acid esters from easily accessible vinylbromides (or vinyl tosylate) and potassium phthalimide. Rh-catalyzed asymmetric hydrogenation of these substrates with TangPhos gave the products with good to excellent enantioselectivities (up to 99% ee).
Versatile Transformations of α,β-Dibromoesters and Ketones in Basic Media under Microwave Irradiation
作者:Jack Hamelin、Aïcha Saoudi、Hadj Benhaoua
DOI:10.1055/s-2003-41054
日期:——
Depending on the reaction medium, α,β-dibromoesters under microwave irradiation may selectively lead to α-bromoalkenes, to alkenes or to (E)-β-bromostyrenes. The corresponding ketones give selectively the α-bromoketones.
Simple and Efficient Copper-Catalyzed Approach to 2,4-Disubstituted Imidazolones
作者:Xiaoyu Gong、Haijun Yang、Hongxia Liu、Yuyang Jiang、Yufen Zhao、Hua Fu
DOI:10.1021/ol1008813
日期:2010.7.16
Some imidazolone derivatives are biological and pharmaceutical active molecules and the chromophores of the fluorescent proteins. In this communication, a simple and efficient approach to 4-arylidene-2-alkyl-4,5-dihydro-1H-imidazol-5-ones (2,4-disubstituted imidazolones) has been developed, and the protocol uses readily available 2-bromo-3-alkylacrylic acids and amidines as the starting materials without addition of any ligand or additive. The reactions were performed under mild conditions. Therefore, the present method will be of wide application in organic chemistry and medicinal chemistry.
Preparation of α-Bromoacrylates: One-Pot Procedure for the Synthesis of Conjugated Acetylenic Carboxylates from Aldehydes with Ph<sub>3</sub>P/Br<sub>3</sub>CCO<sub>2</sub>Et
作者:Doo Jang、Joong-Gon Kim、Dong Kang
DOI:10.1055/s-2008-1032070
日期:2008.2
established the optimal conditions for the Wittig reaction for synthesizing α-bromoacrylates with a high selectivity, and developed a simple and efficient one-pot procedure for preparing various conjugated acetylenic carboxylates in moderate to high yields.