Study On Process Of Preparing Of Aryl Boronate Ester By Ir Catalysized Directed Borylation

Aryl boronates are very important intermediates in modern organic synthesisthat have been deployed in many useful cross coupling reactions. Among the severalroutes of preparing aryl boronates, Ir complex catalysed directly borylation ofaromatic C-H bonds get more and more attentions. However, the application thisreaction to large scale producing aryl boronates still needs to be studied.Pyrene is a popular polycyclic aromatic hydrocarbon, and it is also an importantproduction of modern chemical engineering. In this work, we studied the reactionconditions (including ratio of reactants, temperature, time and amounts of catalyst) ofIr complex catalysed directly borylation of pyrene in detail. The best optimizedprocess condition is determined as the followed: amount of catalyst is5%, thetemperature is60-80oC and reaction time is about8h. Under this optimized condition,the yield of Bpin-Py-Bpin and Py-Bpin can reach to95%and65%, respectively.When excess boron source are used, the main product is2,4,7-borylated pyreneexcept the expected Bpin-Py-Bpin. The research results will provide useful referencefor amplified production in the future.In addition, microwave-accelerated Iridium-catalyzed borylations of severalaromatic C-H bonds were also examined. This way can also be used for synthesis ofbiaryl and heterobiaryl compounds by a one-pot single solvent process for tandemC-H borylation/Suzuki-Miyaura cross-coupling sequences.