[3 + 2] Coupling of Quinone Monoacetals by Combined Acid–Hydrogen Bond Donor
作者:Toshifumi Dohi、Yinjun Hu、Tohru Kamitanaka、Naohiko Washimi、Yasuyuki Kita
DOI:10.1021/ol201886r
日期:2011.9.16
expeditious and efficient [3 + 2] coupling approach of quinonemonoacetals 1 with alkene nucleophiles 2 by the action of an activated Brønsted acid in the presence of a hydrogen bond donor perfluorinated alcohol has been achieved. With the optimized combined acid, the reaction could proceed under mild conditions by only mixing the two reactants to afford the cycloadducts 3 in a short time (within 10
Controlled couplings of quinone monoacetals using reusable polystyrene-anchored specific proton catalyst
作者:Toshifumi Dohi、Yinjun Hu、Tohru Kamitanaka、Yasuyuki Kita
DOI:10.1016/j.tet.2012.07.089
日期:2012.10
Controlled couplings of quinone monoacetals 1 with soft nucelophiles have been achieved using a new and reusable perfluorobenzoic acid (PFBA) immobilized on polystyrene beads as an efficient polymer-anchored specific proton. Various advantages regarding the recovery, reusability, and reproducibility as well as the high chemoselectivity toward quinone monoacetals 1 have been determined as the key features of the cleaner systems with newly developed solid acid promoter for the reactions. (C) 2012 Elsevier Ltd. All rights reserved.
Brønsted Acid-Controlled [3 + 2] Coupling Reaction of Quinone Monoacetals with Alkene Nucleophiles: A Catalytic System of Perfluorinated Acids and Hydrogen Bond Donor for the Construction of Benzofurans
作者:Yinjun Hu、Tohru Kamitanaka、Yusuke Mishima、Toshifumi Dohi、Yasuyuki Kita
DOI:10.1021/jo400613z
日期:2013.6.7
We have developed an efficient Brønsted acid-controlled strategy for the [3 + 2] coupling reaction of quinonemonoacetals (QMAs) with nucleophilic alkenes, which is triggered by the particular use of a specific acid promoter, perfluorinated acid, and a solvent, fluoroalcohol. This new coupling reaction smoothly proceeded with high regiospecificity in regard with QMAs for introducing π-nucleophiles