Reactivity of 3-Styrylchromones as Dienes in Diels-Alder Reactions under Microwave Irradiation: A New Synthesis of Xanthones
作者:Diana C. G. A. Pinto、Artur M. S. Silva、Cristela M. Brito、Angela Sandulache、José R. Carrillo、Pilar Prieto、Angel Díaz-Ortiz、Antonio de la Hoz、José A. S. Cavaleiro
DOI:10.1002/ejoc.200500073
日期:2005.7
Microwave irradiation under solvent-free conditions induced 3-styrylchromones to undergo Diels–Alder cycloaddition reactions with N-methyl- and N-phenylmaleimide as well as with other dienophiles. In some of these reactions the cycloadducts underwent in situ oxidation to give xanthones, whereas in other cases it was necessary to add DDQ as an oxidant. The reactions of 3-styrylchromones with N-methyland
无溶剂条件下的微波辐射诱导 3-苯乙烯基色酮与 N-甲基-和 N-苯基马来酰亚胺以及其他亲二烯体发生 Diels-Alder 环加成反应。在这些反应中的一些反应中,环加合物进行原位氧化以产生氧杂蒽酮,而在其他情况下则需要添加 DDQ 作为氧化剂。3-苯乙烯基色酮与N-甲基和N-苯基马来酰亚胺反应生成环加合物4-芳基-1,3-二氧代-3a,4,11a,11b-四氢吡咯并[3,4-c]氧杂蒽酮,其被氧化为4-芳基-1,3-二氧代吡咯并[3,4-c]氧杂蒽酮与DDQ。3-苯乙烯基色酮与 2-(2-硝基乙烯基)噻吩的反应直接通过 Diels-Alder 反应生成 2-芳基-3-(2-噻吩基)氧杂蒽酮,然后通过 HNO2 消除和氧化。本文所述的3-苯乙烯基色酮的环加成反应是立体选择性的。