合成了一种新型稳定的 V 型催化剂 [(L 2 )V IV O](ClO 4 ),并通过 X 射线衍射 (XRD) 分析和 FT-IR、紫外可见光和 EPR 光谱对其进行了表征,证实了其优异的催化活性。在应用中,使用新开发的催化剂[(L 2 )V IV O](ClO 4 )和H 2 O 2作为绿色氧化剂,通过一锅法在没有添加剂的情况下将醛类快速转化为相应的酯类。开发的方法与广泛的密集取代醛兼容,并允许轻松制备脂肪族、芳香族和杂环酯,包括衍生自 CD 3 的酯OD、甲醇、乙醇、异丙醇、正丁醇、仲丁醇和炔丙醇。令人欣慰的是,许多醇类也通过一锅法直接转化为相应的酯类。我们在本文中公开了两种不同的官能团(醇和醛)以令人满意的收率直接转化为酯(33 个例子),显示了开发的催化剂以一锅法进行各种氧化有机转化的潜力。
N-Heterocyclic Carbene-Mediated Oxidative Electrosynthesis of Esters in a Microflow Cell
作者:Robert A. Green、Derek Pletcher、Stuart G. Leach、Richard C. D. Brown
DOI:10.1021/acs.orglett.5b01459
日期:2015.7.2
An efficient N-heterocyclic carbene (NHC)-mediated oxidative esterification of aldehydes has been achieved in an undivided microfluidic electrolysis C-ell at ambient temperature. Productivities of up to 4.3 g h(-1) in a single pass are demonstrated, with excellent yields, and conversions for 19 examples presented: Notably, the oxidative acylation, reactions were,shown to proceed with a 1:1 stoichiometry of aldehyde and alcohol (for primary alcohols), with remarkably short residence tithes in the electrolysis cell (<13 s), and without added electrolyte.