The kinetic effect of various Diels–Alder and Michael reactions is studied in water and ethylene glycol vs. organic solvents. The rate enhancement is considerable in water, much less in ethylene glycol. It is proposed that strong solvophobic interactions operate in water whereas the kinetic results in glycol are best explained by
hydrogen bonding and polarity effects. From a synthetic point of view, use of the properties of water (hydrophobic
interactions) or ethylene glycol (ionogenic medium) associated with the kinetic effect of high pressure may constitute an interesting multiactivation method to increase chemical reactivity. Examples of triactivation (high pressure catalytic Diels–Alder reactions in ethylene glycol) are given.
在
水和
乙二醇与有机溶vents中,研究了各种Diels-Alder和Michael反应的动力学效应。
水中的速率提升非常显著,而在
乙二醇中则大为减少。提出在
水中的强烈疏溶剂相互作用,而
乙二醇中的动力学结果最好用氢键和极性效应来解释。从合成的角度来看,利用
水的性质(疏
水相互作用)或
乙二醇(离子化介质)与高压动力学效应相结合,可能构成一种有趣的多重激活方法,以提高
化学反应性。给出了三重激活的例子(高压催化Diels-Alder反应在
乙二醇中)。