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Published on: December 16, 2019
Metal-Free Markovnikov-Type Alkyne Hydration under Mild Conditions
Wenbo Liu1, Haining Wang1, Chao-Jun Li1
1Department of Chemistry and FQRNT Center for Green Chemistry and Catalysis, McGill University , 801 Sherbrooke Street West, Montreal, QC H3A 0B8, Canada.
A new Markovnikov-type alkyne hydration method uses triflic acid (TfOH) catalyst under mild conditions. This metal-free protocol achieves high yields and regioselectivity for diverse alkyne substrates.
Area of Science:
- Organic Chemistry
- Catalysis
- Synthetic Methodology
Background:
- Alkyne hydration is a fundamental transformation in organic synthesis.
- Traditional methods often require harsh conditions or transition metal catalysts.
- Development of mild, efficient, and selective alkyne hydration protocols remains a key objective.
Purpose of the Study:
- To develop a novel Markovnikov-type alkyne hydration protocol.
- To achieve hydration under unprecedented mild reaction conditions.
- To demonstrate broad substrate scope and high efficiency.
Main Methods:
- Utilized 20% triflic acid (TfOH) as a catalyst.
- Employed trifluoroethanol as the reaction solvent.
- Conducted reactions at mild temperatures (25-70 °C) with near-stoichiometric water.
Main Results:
- Achieved excellent regioselectivity for Markovnikov addition products.
- Obtained good to excellent yields (average >85%) across various alkyne types.
- Demonstrated broad functional group compatibility and metal-free conditions.
Conclusions:
- The developed TfOH-catalyzed alkyne hydration is a mild and efficient method.
- The protocol offers a valuable alternative to existing alkyne hydration strategies.
- Trifluoroethanol as a solvent is crucial for the protocol's success.
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