Generation of Allylmagnesium Reagents by Hydromagnesiation of 2-Aryl-1,3-dienes.

A protocol for the generation of allylmagnesium reagents from 2-aryl-1,3-dienes was developed using magnesium hydride (MgH2 ) that is generated in situ by solvothermal treatment of sodium hydride (NaH) and magnesium iodide (MgI2 ) in tetrahydrofuran (THF). Downstream functionalization of the resulting allylmagnesium reagents with carbonyl compounds or alkyl (pseudo)halides delivers branched products having an allylic quaternary carbon center, whereas that with chlorosilanes resulted in formation of linear allylsilanes in regio and stereoselective manners. Further derivatizations of the homoallylic alcohols and allylsilanes were also demonstrated.