Synthesis of α-Alkynylnitrones via Hydromagnesiation of 1,3-Enynes with Magnesium Hydride.

A protocol for the synthesis of α-alkynylnitrones from 1,3-enynes has been developed. The process is triggered by hydromagnesiation of 1,3-enynes with magnesium hydride (MgH2), which is prepared in situ through solvothermal treatment of magnesium iodide (MgI2) with sodium hydride (NaH) in tetrahydrofuran. Downstream functionalization of the resulting propargylmagnesium intermediates with organo nitro compounds affords α-alkynylnitrones, which could be used as versatile precursors for the construction of various nitrogen-containing compounds.