Iron-catalyzed reductive magnesiation of oxetanes to generate (3-oxidopropyl)magnesium reagents.

In the presence of FeCl(n)-(bisphosphine) or FeCl(n)-(2-iminomethylpyridine) (n = 2 or 3), 2-substituted oxetanes reacted with Grignard reagents undergoing reductive magnesiation at the 2-position to afford substituted 3-oxidopropylmagnesium compounds, which are useful nucleophiles in reactions with a variety of electrophiles.

Cobalt-catalyzed cross addition of silylacetylenes to internal alkynes.

A CoCl2·6H2O/Zn reagent using 2-(2,6-diisopropylphenyl)iminomethylpyridine (dipimp), 1,2-bis(diphenylphosphino)ethane (dppe), or 1,2-bis(diphenylphosphino)benzene (dppPh) as a ligand effectively catalyzed the cross-addition reaction of silylacetylene to internal alkynes. The reaction of some unsymmetrical internal alkynes, such as 3-arylpropargyl alcohols, proceeded in a highly regioselective manner in the presence of dppe or dppPh but gave a nearly 1:1 mixture of regioisomers in the presence of dipimp. The results of reactions using 1-deuterated 2-silylacetylene revealed that the reaction involves a direct oxidative addition of the silylacetylenic C-H bond to cobalt.

Chain-growth cycloaddition polymerization via a catalytic alkyne [2 + 2 + 2] cyclotrimerization reaction and its application to one-shot spontaneous block copolymerization.

A cobalt-catalyzed alkyne [2 + 2 + 2] cycloaddition reaction has been applied to polymerizations yielding linear polymers via selective cross-cyclotrimerization of yne-diyne monomers, which occurs in a chain-growth manner. Additionally, through control of the alkyne reactivity of the two monomers, this method was efficiently applied to the spontaneous block copolymerization of their mixture. Here we present the proposed mechanism of the catalyst transfer process of this cycloaddition polymerization.