An iodine-catalyzed aerobicoxidative formal [4+2] annulation for the construction of polyfunctionalized pyridines in one step has been developed through the green reaction system of catalytic amounts of molecular iodine and amine in combination with oxygen. Various ketones and aldehydes were able to react with different chalcones and β, γ-unsaturated α-ketoesters through this reaction strategy. Synthetically
An Aminocatalyzed Michael Addition/Iron-Mediated Decarboxylative Cyclization Sequence for the Preparation of 2,3,4,6-Tetrasubstituted Pyridines: Scope and Mechanistic Insights
作者:Mateus L. Stivanin、Marcelo Duarte、Camila Sartori、Naylil M. R. Capreti、Celio F. F. Angolini、Igor D. Jurberg
DOI:10.1021/acs.joc.7b01789
日期:2017.10.6
A novel, scalable strategy for the preparation of 2,3,4,6-tetrasubstituted pyridines is described. This protocol has two steps: an aminocatalyzed addition of ketones to alkylidene isoxazol-5-ones, followed by an iron-mediated decarboxylative cyclization event. Mechanistic insights for both steps are provided based on HRMS-ESI(+) studies.