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Chemo-selective Rh-catalysed hydrogenation of azides into amines
Mattia Ghirardello1, Helene Ledru1, Abhijit Sau1
1School of Chemistry, University of Bristol, Cantock's Close, BS8 3TS, UK.
Carbohydrate Research
|February 17, 2020
Summary
Rhodium on alumina (Rh/Al2O3) offers a chemo-selective catalytic hydrogenation method. This approach effectively reduces azide groups while preserving other sensitive functionalities in carbohydrate and amino acid derivatives.
Area of Science:
- Organic Chemistry
- Catalysis
- Carbohydrate Chemistry
Background:
- Selective reduction of functional groups is crucial in organic synthesis.
- Azide moieties require specific methods for reduction to amines.
- Protecting groups like benzyl and benzyloxycarbonyl are common in carbohydrate and amino acid synthesis.
Purpose of the Study:
- To introduce a chemo-selective reductive catalyst for azide reduction.
- To demonstrate the catalyst's efficacy in the presence of other hydrogenolysis-labile groups.
- To showcase the application of this method in synthesizing complex carbohydrate and amino acid derivatives.
Main Methods:
- Utilized rhodium supported on alumina (Rh/Al2O3) as a heterogeneous catalyst.
- Employed catalytic hydrogenation under mild conditions.
- Tested the catalyst's selectivity with various substrates containing azide, benzyl, and benzyloxycarbonyl functionalities.
Main Results:
- Rh/Al2O3 demonstrated high chemo-selectivity for reducing azide groups.
- The catalyst effectively preserved benzyl and benzyloxycarbonyl groups during reduction.
- Successful application was shown for diverse azide-containing carbohydrate and amino acid derivatives.
Conclusions:
- Rh/Al2O3 is a practical and effective catalyst for chemo-selective azide reduction.
- This method simplifies synthetic routes by avoiding protection/deprotection steps.
- The strategy is valuable for the synthesis of complex molecules in carbohydrate and amino acid chemistry.
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