Chromium catalysts, Nozaki-Hiyama-Kishi reaction

The multi-component procedure is also effective for the chromium-catalyzed addition of organic halides to aldehydes (the Nozaki-Hiyama-Kishi reaction) [73]. The active Cr(II) species is recycled by redox interaction with Mn powder as the stoichiometric co-reductant in the presence of MesSiCl (Scheme 34), which mainly liberates the chromium catalyst from the alkoxide adduct. The chemo- and diastereo-selective addition reaction is performed with a variety of organic halides and alkenyl triflates. In the case of crotyl bromide, the addition is highly stereoconvergent, i.e., the respective anti-... 

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