Synthesis of 1,2-Dihydropyridines Catalyzed by Well-Defined Low-Valent Cobalt Complexes: C–H Activation Made Simple

A convenient one-pot system has been
developed, allowing the synthesis
of highly substituted dihydropyridines via a C–H activation/6π-electrocyclization
pathway. The reaction proceeds with high regioselectivity, and we
disclose the first example of isolated dihydropyridines lacking substitution
in the 2 position. Moreover, the use of a simple well-defined low-valent
cobalt complex without the need for reducing agents or additives in
combination with computational studies provides a clearer insight
into the C–H activation pathway than was previously reported.