A mild, selective and redox-neutral Cp*Ir(III)- and Cp*Rh(III)-catalyzed C–H activation/annulation of salicylaldehydes with fluorovinyl tosylates is reported. The use of monofluorovinyl tosylate favors the synthesis of C2- and C3-substitution-free chromones via C–H activation/β-F elimination/annulation, whereas difluorovinyl tosylate leads to the construction of C2-fluoroalkoxy chromones. Mild reaction
报道了一种温和、选择性和氧化还原中性的 Cp*Ir( III )-和 Cp*Rh( III )-催化的水杨醛与甲苯磺酸氟乙烯酯的 C-H 活化/环化。甲苯磺酸单氟乙烯酯的使用有利于通过C-H 活化/β-F 消除/环化合成无 C2 和 C3 取代的色酮,而甲苯磺酸二氟乙烯酯导致 C2-氟烷氧基色酮的构建。观察到温和的反应条件和良好的官能团耐受性。成功实现了通过卤化、炔基化、烷基化和氢氰化对所得色酮的进一步官能化。
Access to Flavones via a Microwave-Assisted, One-Pot Sonogashira−Carbonylation−Annulation Reaction
作者:Emelia Awuah、Alfredo Capretta
DOI:10.1021/ol901043q
日期:2009.8.6
Palladium complexes of 1,3,5,7-tetramethyl-2,4,8-trioxa-6-phenyl-6-phosphaadamantane are shown to be effective catalytic systems facilitating the sequential application of a microwave-assisted Sonogashira and carbonylative annulation reaction for the preparation of substituted flavones.