A mild efficient iodine-catalyzed synthesis of novel anticoagulants with 2,8-dioxabicyclo[3.3.1]nonane core
摘要:
An efficient coupling of 2-hydroxychalcones/alpha,beta-enones with 4-hydroxycoumarin/5,5-dimethylcyclohexyl-1,3-dione (dimedone) has been accomplished to provide access to a novel class of potential anticoagulants with 2,8-dioxabicyclo[3.3.1]nonane core. The reaction proceeds by Michael-bicycloketalization sequence under iodine catalysis (10 mol %) in aqueous ethanol under reflux. Good to excellent yields, impressive selectivity, absence of byproduct formation, avoidance of toxic organic solvents, and utilization of metal-free water-compatible mild Lewis acid catalyst are the key attractive features of this protocol. (C) 2013 Elsevier Ltd. All rights reserved.
Cerium(<scp>iii</scp>)-catalyzed regioselective coupling of 2-hydroxychalcones and polyphenols: an efficient domino approach towards synthesis of novel dibenzo-2,8-dioxabicyclo[3.3.1]nonanes
作者:Nemai Chand Ganguly、Sushmita Roy、Pallab Mondal
DOI:10.1039/c4ra05927a
日期:——
(5 mol% each) catalyzed coupling of 2-hydroxychalcones with resorcinol/phloroglucinol via regioselective Michael addition–bicyclization cascade. The enhanced nucleophilicity driven reaction of phloroglucinol with two chalcone partners delivered facile access to unprecedented novel bisbicyclic-O,O-ketals. Installation of hydrogen donor phenolic function in the conformationally constrained bicyclic-O