Research On Aldol Reaction And Michael Addition Reaction On Pure Water

Organic solvents are the most common and efficient choice for organic reactions,but their extensive application can cause irreversible damage to the environment.Water as a green environmental reaction medium participating in organic reactions has been expected to reduce the environmental pollution caused by chemical and chemical industry,in line with the trend of the society for the development of green chemistry;in addition,the aqueous reaction often features with unique acceleration effect,excellent reaction selectivity and so on.Therefore,the research on the organic reaction in aqueous phase has important scientific and social value.The reaction using pure water as a reaction medium can be classified into in-water reaction and on-water reaction depending on whether or not the reaction substrate is dissolved in pure water.In view of the fact that pure water reaction has no special requirements on the water solubility of organic substrates,it is more promising to carry out related research.After decades' development,the organic reaction on pure water has not only made great progress in the variety of reaction types,but also in the mechanism exploration.However,pure water reaction is still a minor field in organic synthesis community.Its scarcity can be attributed to the limited successful examples,the lack of guidance from mature theories,as well as the idea contradiction between "non-dissolving can react" in pure water reactions and "non-dissolving can't react" to the deep-rooted view of most chemists.How to convince organic chemists to accept the concept "non-dissolving can react",and consider adopting pure water as the reaction medium(at least not excluding its application),providing more successful examples and breakthroughs in reaction mechanism is obviously the only solution.This thesis aims to expand the pure water reaction paradigm and uncover the mystery of the on-water reaction acceleration effect.The systematic study on the Aldol reaction and the Michael addition reaction on pure water has been carried out.The specific research contents are as follows:(1)A new strategy concerning polyetheramine D230 catalyzed Aldol reaction via on-water mode has been developed.Under the catalytic amount of polyetheramine D230,isatin can react with acetophenone in pure water to produce Aldol adduct efficiently,as 35 kinds of 3-hydroxy-2-indolone compounds were prepared in good to excellent yield.The novel method features in adoption of pure water as the reaction medium,no heating and oxygen-free requirement,convenient operation,good substrates compatibility,thus exhibiting prominent industrial application prospect.In-situ 13C NMR experiments show that the addition of water causes the blue shift of the 2-and 3-position carbon's signals,which is highly likely to be related to the formation of interfacial hydrogen bonds causing the decrease of the electron cloud density of carbon atoms.Hydrogen bonding accelerates the pure water reaction and provides a simple and feasible method for identifying substrates suitable for on-water reactions.The preparation of imine sample and its comparison of the in situ mass spectrometry combined with the newly prepared intermediate imine indicated that the reaction was most likely to proceed through the enamine mechanism.(2)A new method of Michael addition reaction between ?,?-unsaturated ketone and nitromethane promoted by hot water has been developed.Under the optimized conditions,11 addition products have been prepared.The method features with the application of pure water as reaction solvent,reduction of environmental pollution and cost,conformance to the core of green chemistry,providing an important basis for further mechanism exploration.