Brønsted acid UiO-66 MOFs were prepared for the efficient homo-dimerization of 2H-chromenes, which involves a tandem rearrangement/hetero-Diels–Alder reaction sequence.
Iron-Catalyzed Rearrangements and Cycloaddition Reactions of 2<i>H</i>-Chromenes
作者:Yi Luan、Huan Sun、Scott E. Schaus
DOI:10.1021/ol202772k
日期:2011.12.16
Iron(III) salts catalyze the tandem rearrangement/hetero-Diels-Alder reaction of 2H-chromenes to yield tetrahydrochromeno heterocycles. The process can occur as a homodimerization and cycloaddition process using electron-rich dienophiles. Deuterium labeling and mechanistic studies revealed a hydride shift and ortho-quinone methide cycloaddition reaction pathway.
A facile 2<i>H</i>-chromene dimerization through an <i>ortho</i>-quinone methide intermediate catalyzed by a sulfonyl derived MIL-101 MOF
SEM, XRD, FTIR, BET and TGA. An efficient and diastereoselective homo-dimerization of 2H-chromenes catalysis was achieved using the sulfonyl derived MIL-101 MOF as a catalyst. A benzopyranobenzopyran polycyclic structure was generated in high yield and diastereoselectivity under mild catalytic reaction conditions. Furthermore, a regio-isomer was observed when 2H-chromene bears different substitution
research area of o-quinone methides. An efficient approach for the synthesis of chromene derivatives from vinyl o-quinone methides was established via a Brønsted acid catalyzed electrocyclization. By using this methodology, a series of structurally diversified chromenes was synthesized in a highly atom-economic and environmentally benignmanner with generally good to excellent yields (up to 98% yield). This