2023-01- Radical Cyclization of Ynamides to Nitrogen Heterocycles

Zhang, C.; Blanchard, N.; Evano G. Synthesis, 2023, 55, 272.

An efficient radical cyclization of suitably functionalized ynamides to nitrogen-containing heterocycles is reported. Upon reaction with tributyltin hydride in the presence of catalytic amounts of AIBN in toluene at 80 °C, a range of ynamides bearing a N-iodopropyl chain could be smoothly cyclized, in a highly regio- and stereo- selective manner, to the corresponding 2-arylidene-pyrrolidines in good to excellent yields. The exocyclic double bond was in addition shown to be an excellent anchor for further chemical diversification and the generality of this radical cyclization could be highlighted by its extension to the synthesis of other nitrogen heterocycles including piperidines, azepanes, pyrazolidines and hexahydropyridazines.

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2023-02- Regio- and Stereoselective Hydroelementation of SF5-Alkynes and Further Functionalizations

Popek, L.; Cabrera-Trujillo, J. J.; Debrauwer, V.; Blanchard, N.; Miqueu, K.; Bizet, V. Angew. Chem. Int. Ed., 2023, 62, e202300685.

Herein is described a fully regio- and stereoselective hydroelementation reaction of SF5-alkynes with N, O and S-nucleophiles and further functionalization of the corresponding Z-(hetero)vinyl-SF5 intermediates, a suitable platform to access α-SF5 ketones and esters, β-SF5 amines and alcohols under mild reaction conditions.  Experimental and computational comparative studies between SF5– and CF3-alkynes have been performed to highlight and explain the difference of reactivity and selectivity observed between these two fluorinated motifs.

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