Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.
Chemistry. 2022 Jul 26;28(42):e202201329. doi: 10.1002/chem.202201329. Epub 2022 Jun 13.
Herein, the copper-catalyzed borylation of readily available acyl chlorides with bis(pinacolato)diboron, (B pin ) or bis(neopentane glycolato)diboron (B neop ) is reported, which provides stable potassium acyltrifluoroborates (KATs) in good yields from the acylboronate esters. A variety of functional groups are tolerated under the mild reaction conditions (room temperature) and substrates containing different carbon-skeletons, such as aryl, heteroaryl and primary, secondary, tertiary alkyl are applicable. Acyl N-methyliminodiacetic acid (MIDA) boronates can also been accessed by modification of the workup procedures. This process is scalable and also amenable to the late-stage conversion of carboxylic acid-containing drugs into their acylboron analogues, which have been challenging to prepare previously. A catalytic mechanism is proposed based on in situ monitoring of the reaction between p-toluoyl chloride and an NHC-copper(I) boryl complex as well as the isolation of an unusual lithium acylBpinOBpin compound as a key intermediate.
本文报道了铜催化的易得酰氯与双(频哪醇)二硼（B pin）或双（新戊二醇）二硼（B neop）的硼化反应，该反应从酰硼酸酯中高收率地得到稳定的钾酰基三氟硼酸盐（KATs）。温和的反应条件（室温）下可耐受各种官能团，底物含有不同的碳骨架，如芳基、杂芳基和伯、仲、叔烷基。通过修改后处理程序，还可以获得酰基 N-甲基亚氨基二乙酸（MIDA）硼酸酯。该过程可规模化，并适用于将含羧酸的药物在药物后期阶段转化为其酰基硼类似物，这在以前是具有挑战性的。基于对间甲苯酰氯与 NHC-铜（I）硼酸酯配合物之间反应的原位监测以及作为关键中间体的不寻常的锂酰基 BpinOBpin 化合物的分离，提出了一种催化机理。
