A Practical Synthesis of para Di- and Mono-Substituted Benzhydrylamines from Benzhydrol Precursors
作者:Mathieu Laurent、Jacqueline Marchand-Brynaert
DOI:10.1055/s-2000-6391
日期:——
A series of para-substituted benzhydrylamines 6 were obtained by substitution of the corresponding benzhydrol precursors 1 with phenyl carbamate 2 under acidic conditions, followed by basic hydrolysis of the carbamate intermediates 3. One unsymmetrical intermediate 3i has been resolved by preparative chiral chromatography. Subsequent deprotection of the carbamate function led to the recovery of enantiomerically pure (+)- and (-)-4-chlorobenzhydryl amines.
An efficient route to highly enantioenriched tetrahydroazulenes and β-tetralones by desymmetrization reactions of δ,δ-diaryldiazoaceto-acetates
作者:Yuxiao Liu、Yongming Deng、Peter Y. Zavalij、Renhua Liu、Michael P. Doyle
DOI:10.1039/c4cc08255a
日期:——
A highly stereoselective desymmetrization reaction of delta,delta-diaryl-alpha-diazo-beta-ketoesters catalyzed by chiral dirhodium carboxylates forms aromatic cycloaddition products in up to 97% ee.
efficient, convenient and gram-scalable protocol for the acetylation of alcohols with EtOAc as acetyl source and solvent. Various types of alcohols were successfully transformed into according acetylated products. Good to excellent yields were offered by primary alcohols and low to moderate yields were offered by secondary alcohols.