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.