Synthesis of (chlorovinyl)cobaloxime complexes, model complexes of proposed intermediates in the B12-catalyzed dehalogenation of chlorinated ethylenes.

(Chlorovinyl)cobaloxime complexes, (dmgH)2(py)CoR (R = cis-dichlorovinyl, trans-2-chlorovinyl or 1-chlorovinyl, dmgH = dimethylglyoximate) were synthesized from the reaction of chlorinated ethylenes with in situ generated (dmgH)2Co(I) in the presence of pyridine.

One-step synthesis of 3,5-disubstituted-2-pyridylpyrroles from the condensation of 1,3-diones and 2-(aminomethyl)pyridine.

3,5-Disubstituted- and 3,4,5-trisubstituted-2-(2-pyridyl)pyrroles may be synthesized efficiently from the novel condensation of 2-(aminomethyl)pyridine and 1,3-diones. The cyclization reaction was found to proceed through the intermediacy of a (2-pyridyl)methylimine. A marked dependence of the regioselectivity in the reaction of unsymmetrical diones on the presence of additional aminomethylpyridine suggests that two pathways to the product pyrroles are available.