Abstract
The versatile cycloaddition chemistry of the Si-Ni multiple bond in the acyclic (amido)(chloro)silylene→Ni(0) complex 1, [((TMS) L)ClSi→Ni(NHC)(2) ] ((TMS) L=N(SiMe(3) )Dipp; Dipp=2,6-iPr(2) C(6) H(4) ; NHC=C[(iPr)NC(Me)](2) ), toward unsaturated organic substrates is reported, which is both reminiscent of and expanding on the reactivity patterns of classical Fischer and Schrock carbene-metal complexes. Thus, 1:1 reaction of 1 with aldehydes, imines, alkynes, and even alkenes proceed to yield [2+2] cycloaddition products, leading to a range of four-membered metallasilacycles. This cycloaddition is in fact reversible for ethylene, whereas addition of an excess of this olefin leads to quantitative sp(2) -CH bond activation, via a 1-nickela-4-silacyclohexane intermediate. These results have been supported by DFT calculations giving insights into key mechanistic aspects.