An Easy Access to Oxime Ethers byPd‐CatalyzedC—OCross‐Couplingof Activated Aryl Bromides with Ketoximes and Chalcone Oximes

Abstract

Summary of main observation and conclusionAn efficient Pd‐catalyzed method for C—O cross‐coupling of ketoximes and chalcone oximes with activated aryl bromides and bromo‐chalcones has been developed. All oxime ethers were obtained in good to excellent yields by [(π‐allyl)PdCl]2/tBuXPhos (L7) catalyst system. TrixiePhos (L11) was also found to be effective for the oxime coupling. This method offers an easy and smooth coupling of chalcone oximes with activated aryl bromides and bromo‐chalcones, which has not been previously explored.

Oxime Ether Synthesis through O–H Functionalization of Oximes with Diazo Esters under Blue LED Irradiation

“…Traditionally, oxime ethers can be accessed through the condensation of carbonyl compounds with hydroxylamines, which usually requires additional catalysts or additives to accelerate the dehydration process (Scheme a) . The cross-coupling of oximes with arylboronic acids or organic halides is another elegant route to form oxime ether (Scheme b). , However, those methods generally require the use of transition-metal catalysts in high reaction temperatures. In addition, the allylic substitution of oximes in the presence of transition-metal catalysts to obtain oxime ether has also attracted much attention (Scheme c) .…”