Köckinger Manuel, Hanselmann Paul, Hu Guixian, Hone Christopher A, Kappe C Oliver
Center for Continuous Flow Synthesis and Processing (CCFLOW), Research Center Pharmaceutical Engineering GmbH (RCPE) Inffeldgasse 13 8010 Graz Austria.
Institute of Chemistry, University of Graz, NAWI Graz Heinrichstrasse 28 8010 Graz Austria
RSC Adv. 2020 Jun 11;10(38):22449-22453. doi: 10.1039/d0ra04629a. eCollection 2020 Jun 10.
This communication describes the palladium-catalyzed reductive carbonylation of aryl fluorosulfonates (ArOSOF) using syngas as an inexpensive and sustainable source of carbon monoxide and hydrogen. The conversion of phenols to aryl fluorosulfonates can be conveniently achieved by employing the inexpensive commodity chemical sulfuryl fluoride (SOF) and base. The developed continuous flow formylation protocol requires relatively low loadings for palladium acetate (1.25 mol%) and ligand (2.5 mol%). Good to excellent yields of aryl aldehydes were obtained within 45 min for substrates containing electron withdrawing substituents, and 2 h for substrates containing electron donating substituents. The optimal reaction conditions were identified as 120 °C temperature and 20 bar pressure in dimethyl sulfoxide (DMSO) as solvent. DMSO was crucial in suppressing Pd black formation and enhancing reaction rate and selectivity.
本通讯描述了使用合成气作为廉价且可持续的一氧化碳和氢气来源，钯催化芳基氟磺酸盐（ArOSOF）的还原羰基化反应。通过使用廉价的商品化学品硫酰氟（SOF）和碱，可以方便地将酚类转化为芳基氟磺酸盐。所开发的连续流动甲酰化方案对醋酸钯（1.25 mol%）和配体（2.5 mol%）的负载量要求相对较低。对于含有吸电子取代基的底物，在45分钟内可获得良好至优异产率的芳基醛；对于含有供电子取代基的底物，则需要2小时。最佳反应条件确定为在二甲基亚砜（DMSO）作为溶剂的情况下，温度为120°C，压力为20巴。DMSO对于抑制钯黑形成、提高反应速率和选择性至关重要。
