[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
Catalyst-Free Oxidative [3+2] Cycloaddition of Phenols and Styrenes in the Presence of a 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone/1,1,1,3,3,3-hexafluoropropan-2-ol System
作者:Yunxia Wang、Na Cui、Yu Zhao
DOI:10.1055/s-0036-1589082
日期:2017.12
A catalyst-free oxidative [3+2] cycloaddition of phenols and styrenes was developed with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone as the oxidant and 1,1,1,3,3,3-hexafluoropropan-2-ol as the solvent at room temperature. With this method, a broad range of dihydrobenzofurans were efficiently and quickly obtained from readily available phenols and styrenes.
A highly reactive hypervalent iodine dimer, [Ph(CF3COO)I]-O-[I(OCOCF3)Ph], is utilized as successful promoter in the oxidative phenolic coupling with styrenes leading to 2-aryldihydrobenzofurans. The extensions of the substrates in this study have led to the development of a new expeditious construction of the pyrroloindoline structure from aniline and enamide derivatives.