AI Article Synopsis
- - The study addresses the challenge of selectively functionalizing allenic C(sp )-H bonds through radical-mediated hydrogen atom abstraction (HAA), which has been underexplored in synthetic chemistry compared to other C(sp )-H bonds.
- - A novel method using copper catalysis enables the effective cyanation of tri- and di-substituted allenes with high site-selectivity, while achieving lower yields for mono-substituted allenes.
- - A key component of this approach is a steric N-fluoro-N-alkylsulfonamide, which acts as a precursor for the hydrogen atom abstractor, helping to enhance regioselectivity and prevent undesired reactions with the allene.
Article Abstract
While the hydrogen atom abstraction (HAA) from C(sp )-H bond has been well explored, the radical-mediated chemo- and regio-selective functionalization of allenic C(sp )-H bond via direct HAA from C(sp )-H bond of allene remains an unsolved challenge in synthetic chemistry. This is primarily due to inherent challenges with addition of radical intermediates to allenes, regioselectivity of HAA process, instability of allenyl radical toward propargyl radical et al. Herein, we report a copper catalyzed allenic C(sp )-H cyanation of an array of tri- and di-substituted allenes with exceptional site-selectivity, while mono-substituted allene was successfully cyanated, albeit with a low yield. In the developed strategy, steric N-fluoro-N-alkylsulfonamide, serving as precursor of hydrogen atom abstractor, plays a crucial role in achieving the desired regioselectivity and avoiding addition of N-centered radical to allene.
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| http://dx.doi.org/10.1002/anie.202317132 | DOI Listing |
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