rhodium‐catalyzed addition of aryl and alkenyl boronic acids to phthalaldehyde and subsequent intramolecular esterification is described (see scheme; cod=1,5‐cyclooctadiene, dppb=1,4‐bis(diphenylphosphino)butane). The method is facile and practical for accessing 3‐aryl and 3‐alkenyl phthalides in moderate to good yields. Several functional groups are tolerated under the reaction conditions.
An Alternative Method for the Synthesis of γ-Lactones by Using Cesium Fluoride-Celite/Acetonitrile Combination
作者:Khan, Khalid Mohammed、Hayat, Safdar、Zia-Ullah、Atta-ur-Rahman、Iqbal-Choudhary、Maharvi, Ghulam Murtaza、Bayert, Ernst
DOI:10.1081/scc-120024003
日期:2003.9
A variety of 2-(1-bromoalkyl) benzoic acids 4 undergo intramolecular nucleophilic substitution reaction when treated with a CsF-Celite as solid base in acetonitrile under reflux condition to give the corresponding cyclized phthalides in moderate to very good yield. These 2-(1-bromoalkyl) benzoic acids 4 are formed by the alpha-bromination of 2-alkylbenzoic acids 3 using N-bromosuccinimide and a catalytic amount of alpha,alpha'-azoisobutyronitrile in carbon tetrachloride under reflux.