Quantification of the Electrophilicities of Diazonium Ions
作者:Herbert Mayr、Manfred Hartnagel、Klaus Grimm
DOI:10.1002/jlac.199719970111
日期:1997.1
constants of the diazonium counterion. A decrease of the rate constant with increasing solvent donor ability (correlation with Gutmann's donor number) was found. The reactions of diazoniumions with π-nucleophiles roughly follow the correlation lgk (20°C) = s (E + N), previously derived for the reactions of carbocations with nucleophiles. With the E parameters derived for diazoniumions, rate constants
Synthesis of Azobenzenes from Quinone Acetals and Arylhydrazines
作者:M. Carmen Carreño、Gerardo Fernández Mudarra、Estíbaliz Merino、María Ribagorda
DOI:10.1021/jo0498011
日期:2004.5.1
Direct reaction between quinone bisacetals and arylhydrazines gives azobenzenes. The presence of catalytic amounts of cerium ammonium nitrate strongly accelerates the reaction. When the bisacetal has a substituent at the 2,5-cyclohexadiene framework, only one regioisomer is formed. The method represents a simple, mild, and novel synthetic access to differently substituted azocompounds in high to excellent