Lewis Base-catalyzed Ring-opening Reaction Of Activated Cyclopropanes And Oxiranes

Activated cyclopropane and epoxy ethane has been get attention of many scholars in modern chemistry. A lot of literature have articulated with Lewis acid or Bn(?)nsted acid catalytic ring opening reaction of activated cyclopropane and epoxy ethane. The cycloaddition reaction prepared by the intermediates with nucleophilic reagent or its own activity. Cyclization product skeleton also widely exists in natural product, has very important significance.Organic catalysis is a hot field in organic synthesis, organic amine is more widespread in recent years, organic amine is a kind of N atoms and the dissociative electron pair of organic compounds, is a common organic intermediate, it can be with some organic compounds generated macro molecular compounds, can steady increase of molecular complexity. This paper also explore the organic catalytic.There we have studied the activated cyclopropane and epoxy ethane ring opening reaction with Lewis base. The first part studies the 1-acetyl-1-benzoyl amine cyclopropane ring opening to situ generate stable zwitterionic intermediate in some different Lewis bases. The intermediates can exist in the nature of stable and easy separated. Then we are explore the application of zwitterions. The zwitterions with electrophilic reagents can generated some five member compound by one-pot. In the process of experiment, we are amazed to find that if the sodium hydroxide will increase 2.5 times, time extended to 12 hours, products become out of decarbonylation product we also studied the cyclopropane 1,1-diacyl ring opening reaction and its derivatives, found that the reaction mechanism is undergo zwitterion. If prolonged the time, increase the temperature, we will generate 2,3-dihydrofuran products. And 1,1-diester cyclopropane compounds under the reaction of organic alkali, also can happen open ring reaction, it is generated inner salt with carboxylic acid groups. This reaction mechanism will be speculation.The second part is mainly studied the organic amine catalyzed ring opening reaction of epoxy ethane derivatives. The addition of organic base (DABCO) made of epoxy ethane C-O bond broken, formed a new ternary heterocyclic intermediates, and acyl migration, eventually DABCO as a leaving group produced allyl ester compound. And DABCO act as a catalyst in this reaction. This research has high atom utilization, environmentally friendly, and simple operation.