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DOI: 10.1055/s-0033-1341213
Synthesis of 2-Substituted 2-Azetines by Lithiation of N-Boc-2-azetines
Publication History
Publication Date:
17 April 2014 (online)
Significance
The authors report the regioselective C2-lithiation and functionalization of N-Boc-2-azetines. For the synthesis of the appropriate 2-subsituted 2-azetines, the more stable N-Boc-3-methoxyazetidine precursors are used, which are treated with 2.5 equivalents of s-BuLi to give, after elimination of LiOMe, the corresponding 2-lithiated 2-azetines. These lithium reagents further react with various electrophiles to afford a wide range of functionalized azetines in high yields.
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Comment
Generally, 2-azetines are known for their instability since they are prone to electrocyclic ring openings, and thus are difficult to handle in laboratory. Using the reported strategy, these 2-azetines are generated in situ from commercially available N-Boc-3-methoxyazetidine, which undergoes α-lithiation–elimination after treatment with s-BuLi. Hence, various 2-substituted 2-azetines are accessible making this protocol practically very important.
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