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Synthesis 2023; 55(23): 3927-3946
DOI: 10.1055/a-2126-0720
DOI: 10.1055/a-2126-0720
feature
Studies on Selective Metalation and Cross-Coupling Reactions of Oxazoles
Generous financial support by the Deutsche Forschungsgemeinschaft (DFG, ME-2756/9-1) is gratefully acknowledged.
Abstract
A general study on selective functionalization of unsubstituted oxazole is reported. Specific halogenation at C2 and C5 was enabled by a sequential deprotonation strategy that was based on the different pK a values of these positions, while a halide at C4 may be introduced by an optimized halogen dance reaction. Efficient protocols for subsequent sp2–sp2 and sp2–sp3 cross-coupling reactions of the derived oxazolyl halides were then established. This modular approach was applied in the total synthesis of ajudazol A and a selected analogue, demonstrating the general feasibility of these conditions in a complex setting.
Key words
oxazole - halogen dance reaction - halogenation - Negishi/ Suzuki cross-coupling - ajudazol ASupporting Information
- Supporting information for this article is available online at https://doi.org/10.1055/a-2126-0720.
- Supporting Information
Publication History
Received: 22 May 2023
Accepted after revision: 10 July 2023
Accepted Manuscript online:
10 July 2023
Article published online:
24 August 2023
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For syntheses of fragments and analogues, see:
For syntheses of ajudazol analogues, see:
For full stereochemical determination and total syntheses of ajudazol B, see: