Silyl Ketene Imines
21 February 2014 (online)
Silyl ketene imines (SKIs) are a wide variety of nucleophiles possessing a pair of orthogonal substituents within a cumulene group and can have other functional groups, including alkenes, allenes, ketenes, and amines. SKIs can be employed in a wide range of reactions involving C–C bond formation and/or the formation of stereogenic centers.
When combined with an appropriate catalyst and ligand, C–C bond forming reactions with SKIs are highly stereoselective. SKIs can be converted into nitriles which are precursors of many other functional groups including carboxylic acids, amines, and aldehydes. One of the first synthetic applications of SKIs was described in 1987: a Diels–Alder [4+2] cycloaddition stating a versatile method to obtain anilines and cyclohexanones, leading to a range of aromatic amines in 52–89% yield.
Due to their geometry and the presence of two orthogonal substituents, SKIs have proven to be excellent nucleophiles in order to obtain stereogenic centers.
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