Amidato complexes

Ru(i7-C5H5)(CN)(PMe3)2] results, but with R=Me, the product is the amidato complex [Ru(Tj-C5H5)(NHCOMe)(PMe3)2] (227). 

Additional experiments with the same catalyst source showed further that addition of a base such as sodium acetate or sodium carbonate also promoted the syn-aminopalladation pathway. Obviously, under basic conditions, aminopalla-dation occurs through alkene insertion into a palladium amidato complex with a defined Pd-N bond [45]. Additional experiments by Stahl and White [46] employing an isolated palladium suUbnamidato complex and its intramolecular aminopallada-tion product suggested the alkene insertion reaction to be reversible in nature but to be turned over irreversibly in the presence of molecular dioxygen. Electronically enriched amidates favor the alkene insertion reaction. 

K-atoms present in 1. This was attributed to the more organized (rigid) structure of these complexes as a result of cation-jr interactions. Therefore, it is possible that an excess of inorganic base increases the enantioface-selectivity of the reaction via better stereo-differentiation within K-amidato complexes on one hand, while on the other hand, a background base-catalyzed reaction produces a racemic mixture. Due to competition of these two reactions, the observed enantioselectivity may appear not to depend on the presence/absence of a large excess of inorganic base. 2 ... 

Figure 1.23 Transition states leading to R- and S-products optimized under DFT2i8 2iVcoB97X-D33VSDD(Ru)/6-31G (C, H,N, 0,P, K)/SMD(propan-2-olp3 level of theory on the full model of fra s-[RuH2 (S)-BINAP (S, S)-DPEN)] and its K-amidato complexes with acetophenone. The enantioselectivity for each complex is calculated based on difference in electronic energy using absolute rate theory. Some H-atoms are omitted for the ball and stick model. (Reprinted with permission from Dub, P. A. et al, Dalton Trans., 45,6756-6781. Copyright 2016 Royal Society of Chemistry.)...

Similar zwitterionic complexes have also been prepared by reacting B(G6Fs)3 with Ni(77 -benzyl)(a-iminocarbox-amidato) 86 addition of the Lewis acid to the O atom of the a-iminocarboxamidato moiety furnishes the product. Analogous zwitterionic Ni-(77 -2-methylallyl) 87 and Ni-( 7 -benzyl) 88 complexes supported by... 

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