A novel Pd-catalyzed/Cu-mediated oxidativecyclization has been developed for the synthesis of trisubstituted oxazoles, which is thought to proceed through cascade formation of C-N and C-O bonds. In this protocol, four hydrogen atoms were removed and water was used as the oxygen atom source.
作者:Alexey Yu. Dubovtsev、Dmitry V. Dar'in、Vadim Yu. Kukushkin
DOI:10.1002/adsc.201900097
日期:2019.6.18
Three‐component [2+2+1] gold(I)‐catalyzed reaction of internalalkynes (alkynyl esters or ‐ketones), nitriles, and 2‐chloropyridine N‐oxide led to a wide range of fully substituted 1,3‐oxazoles (32 examples; up to 92% isolated yields). Nitrile R3CN species, employed in the reaction as both reactants and solvents, comprise conventional nitriles (R3=Alk, Ar) and also push‐pull systems such as cyanamides
NIS-TBHP promoted oxidative coupling of C N and C O bonds: A metal-free approach to polysubstituted oxazoles
作者:Shengxiang Yang、Yuzhu Yang、Fei Li、Xiaolan Liu
DOI:10.1016/j.tetlet.2020.151846
日期:2020.5
A metal-free approach to polysubstituted oxazoles via the oxidative coupling of readily available benzylamines and 1,3-dicarbonyl derivatives in the presence of an external base has been developed. A variety of functional groups on both of the starting materials are tolerated using this method, affording the corresponding oxazoles in moderate to good yields. Iodination was proposed as the initiation