Lewis acid-promoted electron transfer deoxygenation of epoxides, sulfoxides, and amine N-oxides: the role of low-valent niobium complexes from NbCl5 and Zn
作者:Kyungsoo Oh、William Eric Knabe
DOI:10.1016/j.tet.2009.02.013
日期:2009.4
A mild and operationally simple deoxygenation of epoxides, sulfoxides, and amine N-oxides is described using a sub-stoichiometric amount of low-valent niobium complexes generated in situ from commercially available NbCl5 and zinc dust. The deoxygenation proceeds by a reductive cleavage of polarized O–C/O–N/O–S bonds through a single electron transfer from zinc metal to the niobium–substrate complex
Abstract Reaction of the protected glycidol derivatives (1A-C) with a wide variety of Grignard reagents (2a-h) in the presence of catalyticamount of CuCN provided the corresponding monoprotected diol derivatives (3) in a highly regioselective manner.
Nickel-Catalyzed Regiodivergent Opening of Epoxides with Aryl Halides: Co-Catalysis Controls Regioselectivity
作者:Yang Zhao、Daniel J. Weix
DOI:10.1021/ja410704d
日期:2014.1.8
Epoxides are versatile intermediates in organic synthesis, but have rarely been employed in cross-coupling reactions. We report that bipyridine-ligated nickel can mediate the addition of functionalized arylhalides, a vinylhalide, and a vinyl triflate to epoxides under reducing conditions. For terminal epoxides, the regioselectivity of the reaction depends upon the cocatalyst employed. Iodide cocatalysis