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.

Iron-Catalyzed Reductive Magnesiation of Oxetanes to Generate (3-Oxidopropyl)magnesium Reagents. -A facile method for the preparation of substituted 3-oxidopropylmagnesium compounds from 2-and 2,3-substituted oxetanes via a novel iron-catalyzed reductive magnesiation reaction is presented. The magnesium compounds undergo subsequent reaction with electrophiles. -(SUGIYAMA, Y.-K.; HEIGOZONO, S.; OKAMOTO*, S.; Org. Lett. 16 (2014) 24, 6278-6281, http://dx.doi.org/10.1021/ol503191w ; Dep. Mater. Life Chem., Fac. Eng., Kanagawa Univ., Yokohama 221-8686, Japan; Eng.) -B. Bergmann 21-042

A novel process for the reductive magnesiation of 2-substituted oxetanes and the metalative cyclization of ω-alkynyl oxetanes is developed using n-propylmagnesium chloride in the presence of an iron catalyst. The generated intermediate organomagnesium compounds react with electrophiles. The reactions of 2,3-disubstituted oxetanes and their subsequent allylation with allyl halides in the presence or absence of copper(I) cyanide as the catalyst is studied with a unique switching of stereoselectivity being observed in the absence or presence of copper(I) cyanide. In addition, it is found that the metalative cyclization of 3-substituted 2-alkynyl oxetanes proceeds in an anti-selective manner starting from both synand anti-substrates. In all cases, the stereochemistry at the 2-position of the oxetanes is lost during the reactions suggesting the involvement of a radical process.