Formation of Di-<i>tert</i>-butylurea from a Mononuclear Iron Tris(isocyanide) Complex
作者:Anitha S. Gowda、Andreas Baur、Carl A. Scaggs、Jeffrey L. Petersen、Jessica M. Hoover
DOI:10.1021/acs.organomet.6b00687
日期:2016.11.14
We report the synthesis and characterization of the tripodal iron tris(isocyanide) complexes [Tm-R'Fe(CNR)(3)](OTf) (R = tBu, Ad; R' = Me, Ph, Mes). These complexes generate the corresponding disubstituted ureas when treated sequentially with a reductant (KC8) and a proton source (H2O). A series of labeling experiments indicate air to be the source of the urea oxygen, while the urea carbon is derived from the isocyanide. Crossover experiments indicate a key role for H2NR in the formation of the disubstituted urea, and we propose a pathway for urea formation that involves a diaminocarbene intermediate that is formed from H2NR attack on a bound isocyanide ligand.