Bisoxazolines nickel catalysts

Scheme 2.22 Conjugate addition of dimethylaluminum TMS-acetylide to cyclo-hex-2-enone with a preformed bisoxazoline nickel catalyst.

Scheme 2.31 Early conjugate addition of nitromethane to o,p-unsaturated amides of 3,5-dimethylpyrazole with an in situ generated bisoxazoline nickel catalyst reported by Kanemasa in 2002.

Vinylogous Mukaiyama-Michael additions of 2-trimethylsilyloxyfuran to 3-alkenoyl-2-oxazolidinones to provide 7-butenolides were shown to be /7-selective. The reaction could be rendered enantioselective in the presence of a (T symmetric copper-bisoxazoline complex <1997T17015, 1997SL568> or a l,T-binaphthyl-2,2 -diamine-nickel(ii) complex as catalyst, as depicted in Equation (16) <2004CC1414>. 

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