Reduction of Carbonyl Compounds with Ammonia-Borane in Water
|green chemistry the reaction in water amine-borane methylamine-borane the reduction of carbonyl compounds
Green chemistry is called environmental friendly chemistry, its main features are: make full use of resources and energy, using nontoxic and harmless reactants; under nontoxic and harmless condition, reducing wastes; improve the utilization rate of atoms, to achieve "zero emissions" and produce environmental friendly products. The traditional chemical industry brings benefit to mankind, at the same time do harm to the human living environment. So the concept of green chemistry takes the high attention of scientists, engineers and all of society, when it’s raised. So far, chemists in the research of green chemistry have adopted the following methods: water as solvent in organic reactions; ionic liquids as solvent in synthetic reactions; the application of supercritical fluid; Solvent-free solid-phase synthesis; microwave application in organic synthesis; the transition metal promoting organic reactions. The water in nature is rich, and it is cheap, readily available and ero-friendly. Organic reactions in aqueous solution accord with research focus and direction of the modern synthesis of green chemical.The reduction of carbonyl compounds to corresponding alcohols is an important kind of organic reaction and widely used in organic synthesis. Borane derivatives are one kind of important reducing reagents including boranes of containing nitrogen, phosphorus, sulfur, oxygen and so on. They are widely used in reducing the unsaturated bonds, such as the double bond beween the carbon and carbon, carbon and nitrogen, carbon and oxygen. Compared with the traditional reagents, the amine-boranes have many advantages, such as mild condition, short reaction time and higher yield, better selectivity etc. So the research on amine-borane compounds has become one of the hot topics in borane chemistry.This dissertation reviewed the research progress of the reactions in water and the borane compouds’applications in organic synthesis based on more than 100 literatures. Two amine-boranes are studied to reduce dozens of different aldehydes and ketones in water. The relationship of the yield and the condition with the structures of carbonyl compounds is discussed. Results show that amine-borane and methylamine-borane are two efficient, mild, selective reagents. They can selective reduced aldehydes and some active ketones in water, without affecting ester group, alkene, nitro group and some sensitive protection groups such as benzyl, Ts, trityl, Ac, benzoyl, silyl. And the structure of products is determined by ~1H NMR.