3.5.6.7 Esterification

Cobalt(II) chloride has been considerably studied as Lewis acid for the acylation of alcohols and amines with acylating agents such as acid chloride, acetic anhydride and acetic acid. The acylation of alcohols with acetic acid is attractive where water is generated by-product (Scheme 13).

Scheme 13

3.5.6.7 Cross-Coupling Reaction

Cobalt(II)-1,10-phenanthroline has been recently used for intramolecular cyclization of amidines to give 2-aryl benzimidazoles in high yield (Scheme 14). The reaction is general, efficient and operates at moderate temperature.

Scheme 14