Templated C–C and C–N Bond Formation Facilitated by a Molybdenum(VI) Metal Center

Preparation
of molybdenum dioxido complexes with novel iminophenolate ligands
bearing pendant secondary amide functionalities led to unprecedented
C–C and C–N coupling reactions of two α-iminoamides
upon coordination. The diastereoselective cyclization to asymmetric
imidazolidines occurs at the metal center in two consecutive steps
via a monocoupled intermediate. A meaningful mechanism is proposed
on the basis of full characterization of intermediate and final molybdenum-containing
products by spectroscopic means and by single-crystal X-ray diffraction
analyses. This process constitutes the first example of a diastereoselective
self-cyclization of two α-iminoamides.