Electroreductive Intermolecular Coupling of Chromones with Benzophenones: Synthesis of 2-Diarylmethylchromones and Tetrasubstituted Furans
作者:Naoki Kise、Hiroaki Nagamine、Toshihiko Sakurai
DOI:10.1002/ejoc.201900519
日期:2019.6.16
The electroreductive coupling of chromones with benzophenones in the presence of TMSCl gave adducts reacted at the 2‐position of chromones as trimethylsilyl ethers. From 3‐methyl‐ and 3‐phenylchromones, 2,3‐cis‐adducts were formed predominantly. 2‐Diarylmethylchromones were obtained by dehydrosiloxylation of the adducts. Tetrasubstituted furans were also synthesized from the adducts through ring‐opening
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。