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过渡金属催化的炔烃绿色氧化研究
Transition Metals-Catalyzed Green Oxidation of Alkynes
【作者】 任伟；
【导师】 万小兵；
【作者基本信息】 苏州大学 ， 有机化学， 2010， 硕士
【摘要】 本论文研究过渡金属催化炔烃绿色氧化成1,2-二羰基类化合物。主要有两部分组成:1.钯催化的炔烃Wacker型绿色氧化研究我们发展了一种炔烃Wacker型氧化体系:溴化钯作为催化剂,溴化铜作为助催化剂,氧气作为最终氧化剂,1,4-二氧六环和水作为混合溶剂,60oC反应24 h。与以往炔烃氧化成双羰基反应相比,本体系的优点在于:1).水做产物中氧的供体,氧气作为最终氧化剂,反应对环境友好,符合绿色化学发展的要求。2).反应条件温和,不需要强氧化剂,也不需要特殊的配体,操作安全简单,对官能团的兼容性高,底物范围广,催化效率高。3).通过控制实验和理论计算,对水的进攻和溴化铜的作用提出了合理的解释。2.钌催化的炔烃绿色氧化研究本体系用Ru(cymene)Cl2]2做催化剂,碘为添加剂,过氧叔丁醇作氧化剂,将一系列炔烃氧化成1,2-二羰基化合物。本体系具有以下优点:1).反应操作简单,直接在空气下进行即可。反应条件温和,使用过氧叔丁醇做氧化剂,对环境友好。2).反应催化剂高效。催化剂用量只有十万分之一当量,TON高达420 000,是迄今为止最高效的过渡金属催化氧化体系。此外,该体系可以放大到摩尔级且催化效率仍然很高,因此该体系具有潜在的工业应用价值。3).反应底物广,官能团兼容性高。4).我们将二羰基产物进行原子发射光谱检测,发现产物中不含有金属钌。这说明一般过渡金属催化反应中金属残留的问题在本体系中并不存在。
【Abstract】 Transition metal catalyzed green oxidations of alkynes are included in this thesis, which is composed with two parts as follows:1. Wacker-Type Oxidation of Alkynes into 1,2-Diketones Using Molecular OxygenIn this section, we describe an intriguing new Wacker-type oxidation of alkynes catalyzed by PdBr2 and CuBr2, which opens an efficient access to 1,2-diketones using molecular oxygen as the ultimate oxidant. Under the optimized conditions, a variety of alkynes bearing a wide range of functional groups, including diarylalkynes, arylalkylalkynes and dialkylalkynes, were compatible substrates in this transformation. Based upon experimental observations and literatures, a plausible mechanism, involving sequential attacks of water molecules, was proposed. A better understanding of the experimental observations was achieved by DFT calculations.2. Ruthenium-Catalyzed Alkynes Oxidation with Part-per-Million Catalyst LoadingsThe combination of [Ru(cymene)Cl2]2, I2 and TBHP affords an efficient catalytic system for the green oxidation of a variety of alkynes, giving the corresponding 1,2-diketones in high to excellent yields. Two noteworthy features of the method are extremely high catalyst productivity (TON up to 420 000) and scale-up to 1 mol, thus implying the feasibility of industrial/practical applications. Importantly, no residual ruthenium impurity was detected by ICP mass analysis in the 1,2-diketone products after recrystallization or column chromatography purification. Based upon 13C NMR and 18O labeling experiments, formation of iodonium ion and water as reagent were proposed in the catalytic cycle.