This paper describes a facile, efficient, and clean synthesis of various pyrazolones by employing T3P® as a catalyst and performing the reaction under microwave irradiation. This two-step, one-pot reaction proceeded readily and tolerated a variety of functional groups. A wide range of pyrazolone derivatives were obtained in good to excellent yields.
Chiral Binaphthyl Box-Copper-Catalyzed Enantioselective Tandem Michael–Ketalization Annulations for Optically Active Aryl and Heteroaryl Fused Bicyclicnonanes
作者:Wei-Tai Fan、Xiao-Peng Yang、Hao-Peng Lv、Xing-Wang Wang、Zheng Wang
DOI:10.1021/acs.orglett.0c01221
日期:2020.5.15
The combination of chiral binaphthyl box-copper(II) with triflimide (Tf2NH) was identified as an efficient catalytic system for the asymmetric Michael/ketalization of (E)-2-hydroxyaryl-2-oxobut-3-enoates or (E)-ethyl 4-(2-aminoaryl)-2-oxobut-3-enoates with pyrazolone derivatives. The corresponding asymmetric tandem reactions provided a series of enantioenriched aryl and heteroaryl fused 2,8-O,O- or O,N-bicyclo[3.3.1]nonanes in high yields with excellent enantio- and diastereoselectivities.
MCPHERSON H. L.; PONDER B. W., J. HETEROCYCL. CHEM. <JHTC-AD>, 1976, 13, NO 4, 909-911