Johnson Joel S, Chong Eugene, Tu Kim N, Blum Suzanne A
Department of Chemistry, University of California, Irvine, California 92697-2025, United States.
Organometallics. 2016 Mar 14;35(5):655-662. doi: 10.1021/acs.organomet.5b00939. Epub 2016 Feb 18.
In the present study, the oxyboration reaction catalyzed by IPrAuTFA in the presence and absence of NaTFA has been examined with kinetic studies, mass spectrometry, and H NMR and B NMR spectroscopy. Data from monitoring the reactions over the temperature range from 30 to 70 °C, the catalyst range from 1.3 to 7.5 mol %, and the NaTFA additive range from 2.5 to 30 mol % suggests a mechanism that involves rate-determining catalyst generation. Data from additive studies that replaced NaTFA with NaBARF (BARF = tetrakis[3,5-bis(trifluoromethyl)phenyl]borate) or BuNTFA as an alternative additive suggest that catalyst quenching from residual NaCl remaining from a one-pot substrate synthesis/reaction method is the cause of this effect, despite the low solubility of this NaCl byproduct in toluene. Material produced through an alternative, sodium chloride free substrate synthesis exhibited faster reaction rates, consistent with a change in rate-determining step that depended on the substrate synthesis route.
在本研究中，通过动力学研究、质谱分析以及氢核磁共振和硼核磁共振光谱，对在有无三氟乙酸钠（NaTFA）存在的情况下，由1,3-双（2,6-二异丙基苯基）咪唑鎓金（I）三氟乙酸盐（IPrAuTFA）催化的硼氢化反应进行了研究。在30至70°C的温度范围内、1.3至7.5 mol%的催化剂范围内以及2.5至30 mol%的NaTFA添加剂范围内监测反应得到的数据表明，其反应机理涉及速率决定步骤的催化剂生成。用四[3,5-双（三氟甲基）苯基]硼酸钠（NaBARF，BARF = tetrakis[3,5-bis(trifluoromethyl)phenyl]borate）或三氟乙酸叔丁酯（BuNTFA）替代NaTFA作为替代添加剂的添加剂研究数据表明，尽管该氯化钠副产物在甲苯中的溶解度较低，但由一锅法底物合成/反应方法中残留的氯化钠导致的催化剂猝灭是造成这种影响的原因。通过另一种无氯化钠的底物合成方法制备的材料表现出更快的反应速率，这与取决于底物合成路线的速率决定步骤的变化一致。
