Saturated and benzylic organomagnesium compounds are shown to readily undergo addition reactions with the conjugated enynes H C HCH 2 R′, with R′ = alkyl, OH, OC 4 H 9 , NHC 2 5 , N(C 2 H 5 ) 2 , by refluxing for several hours in benzene or toluene. ... This reaction leads to both υ-acetylenic compounds (1,2-addition) and β-allenic compounds (1,4-addition) . ... Les magnésiens saturés et benzyliques donnent lieu à une réaction d'addition aux ...