Room Temperature Coupling of Aryldiazoacetates with Boronic Acids Enhanced by Blue Light Irradiation
作者:Amanda F. Silva、Marco A. S. Afonso、Rodrigo A. Cormanich、Igor D. Jurberg
DOI:10.1002/chem.201905812
日期:2020.5.4
visible-light-promoted photochemical protocol is reported for the coupling of aryldiazoacetates with boronic acids. This photochemicalreaction shows great enhancement compared to the same protocol performed in the absence of light. Except for a few cases, the room temperature coupling in the dark (thermal process) generally does not work. When it does, it is likely to also involve free carbenes as key intermediates
Photoinduced Proton‐Transfer Reactions for Mild O‐H Functionalization of Unreactive Alcohols
作者:Sripati Jana、Zhen Yang、Fang Li、Claire Empel、Junming Ho、Rene M. Koenigs
DOI:10.1002/anie.201915161
日期:2020.3.27
hexafluoroisopropanol and the diazoalkane acts as an unreactive hydrogen‐bonding complex. Only after photoexcitation does this complex undergo a protonation‐substitution reaction to the reaction product. Investigations on the applicability of this photochemical transformation show that a broad variety of acidic alcohols can be subjected to this transformation and thus demonstrate the feasibility of
Blue Light-Emitting Diode-Mediated <i>In Situ</i> Generation of Pyridinium and Isoquinolinium Ylides from Aryl Diazoesters: Their Application in the Synthesis of Diverse Dihydroindolizine
作者:Saibal Sar、Souvik Guha、Tejas Prabakar、Debajit Maiti、Subhabrata Sen
DOI:10.1021/acs.joc.1c01209
日期:2021.9.3
1/2, aryl diazoesters 3, and acrylic ester/3-alkenyl oxindoles 5/6 provide various dihydroindolizines 7 to 9 in excellent yield. The principle of the strategy is photolytic generation of nitrogen ylidesfrom N-heteroarenes and aryl diazoesters and their subsequent [3 + 2] cycloaddition reaction with dipolarophiles. Detailed mechanistic analysis of the transformation through control experiments establishes
Blue LED-Mediated N–H Insertion of Indoles into Aryldiazoesters at Room Temperature in Batch and Flow: Reaction Kinetics, Density Functional Theory, and Mechanistic Study
作者:Debajit Maiti、Ranajit Das、Subhabrata Sen
DOI:10.1021/acs.joc.0c02649
日期:2021.2.5
blue light-mediated N–H insertion of indole and its derivatives into aryldiazoesters has been reported in a batch and flow strategy to afford the corresponding N-alkylated product in moderate-to-excellent yield. Detailed high-performance liquid chromatography-based reaction kinetics measurements, control experiments, and kinetic isotope effect reveal that 3-substitutedindoles with electron-withdrawing
Rhodium(II)/Chiral Phosphoric Acid-Cocatalyzed Enantioselective O-H Bond Insertion of α-Diazo Esters
作者:Yiliang Zhang、Yuan Yao、Li He、Yang Liu、Lei Shi
DOI:10.1002/adsc.201700572
日期:2017.8.17
phosphoric acid system has been developed for the asymmetric catalytic insertion of α‐diazo esters into the O–H bond of carboxylic acids to generate an array of synthetically useful α‐hydroxy ester derivatives in good ee (up to 95% ee). Furthermore, the substrate scope could be successfully extended to a range of phenols and alcohols with high yield (up to 92%) and excellent enantioselectivity (up to 97%)