The reactions of 2-pyrones and coumarins with hydrochlorosilane, elemental selenium, and 4-dimethylaminopyridine (DMAP) gave 2-selenopyrones and selenocoumarins in moderate to good yields. Their fo...
Rh(III)-Catalyzed [3 + 3] Annulation Reaction of Cyclopropenones and Sulfoxonium Ylides toward Trisubstituted 2-Pyrones
作者:Peng Zhou、Wei-Tao Yang、Anis Ur Rahman、Guigen Li、Bo Jiang
DOI:10.1021/acs.joc.9b02253
日期:2020.1.17
A new Rh(III)-catalyzed [3 + 3] annulation reaction between cyclopropenones and β-ketosulfoxonium ylides has been reported, enabling metal carbene insertion to access a wide range of trisubstituted 2-pyrones with moderate to excellent yields via C-C single-bond cleavage, in which sulfoxonium ylides serve as potential safe precursors of metal carbenes. This reaction occurred under redox-neutral conditions
Novel fluorescent 3,6-diaryl-4-phenyl-2-pyridone derivatives were synthesized and their fluorescent properties were investigated. These compounds emit intense brilliant blue fluorescence only in the solid state, not in solution. An electron-donating substituent on the 6-phenyl group caused a red-shift in fluorescence maxima.
The DMAP-catalyzed [3+3] annulation of cyclopropenones with α-bromoketones was developed for a convenient synthesis of 2-pyrones. The mechanism may proceed in a pyridium ylide-initiated ring opening of cyclopropenones, followed by elimination of DMAP catalyst, and final 6π-electrocyclization.