Chemoselective Deprotonations of a Cationic Zirconium Primary Amido Complex to Either a Neutral Zirconium Terminal Imido or a Noninterconverting Tautomer

Chemoselective deprotonation of {Cp*Zr(NHtBu)[N(iPr)C(Me)N(iPr)]}[B(C6F5)4] (2a) cleanly provides either
the neutral enolamide, Cp*Zr(NHtBu)[N(iPr)C(CH2)N(iPr)] (5),
or the terminal imido, Cp*Zr(NtBu)[N(iPr)C(CH3)N(iPr)] (6).
These two tautomers do not interconvert, and no evidence was
obtained for deprotonation of 2a in the presence of an excess
of the primary amine tBuNH2.