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Preparation of a Corannulene-functionalized Hexahelicene by Copper(I)-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units
Published on: September 18, 2016
Copper catalysed azide-alkyne cycloaddition (CuAAC) in liquid ammonia
Pengju Ji1, John H Atherton, Michael I Page
1IPOS, The Page Laboratories, Department of Chemical and Biological Sciences, The University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK.
Organic & Biomolecular Chemistry
|August 30, 2012
Summary
Copper(I) catalyzed azide-alkyne cycloaddition (CuAAC) reactions in liquid ammonia provide high yields of 1,4-triazoles at room temperature. This green chemistry approach offers efficient product isolation via ammonia evaporation, suitable for industrial applications.
Area of Science:
- Organic Chemistry
- Green Chemistry
Background:
- Copper(I) catalyzed azide-alkyne cycloaddition (CuAAC) is a vital reaction in synthetic chemistry.
- Conventional solvents pose environmental and recovery challenges.
Purpose of the Study:
- To investigate the efficacy of liquid ammonia as a solvent for CuAAC reactions.
- To explore the reaction kinetics and mechanism in liquid ammonia.
Main Methods:
- Performing CuAAC reactions in liquid ammonia at room temperature.
- Analyzing reaction yields and product purity.
- Conducting kinetic studies and deuterium exchange experiments.
Main Results:
- Exclusive formation of 1,4-substituted 1,2,3-triazoles with up to 99% yield.
- Reduced catalyst loading (0.5 mole%) compared to conventional solvents.
- Facile product isolation through simple ammonia evaporation.
Conclusions:
- Liquid ammonia is an effective and green solvent for CuAAC reactions.
- The reaction proceeds efficiently with terminal alkynes and shows second-order dependence on catalyst concentration.
- The enhanced alkyne acidity in liquid ammonia facilitates the cycloaddition.
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