Samarium catalyzed processes

For an electrochemical samarium-catalyzed pinacol coupling process, see Leonard, E. Dunach, E. Perichon, J. J. Chem. Soc., Chem. Commun. 1989, 276-277. 

In a process similar to Ishii s previously developed samarium catalyzed multicomponent process <98JOC6234>, Ranu describes an efficient three-component coupling of a,(3-unsaturated aldehydes or ketones 12, an amine 13 and a nitroalkane 14 on the surface of silica gel or alumina without any solvent under microwave irradiation affording the polysubstituted pyrroles 15 <01T4767>. 

Other Transition Metals. The rather general validity of the chlorosilane-based catalysis concept is further substantiated by some recent examples of pinacol coupling processes catalyzed either by low-valent vanadium ([CpV(CO)4] cat., Zn, chlorosilane) [16j or low-valent samarium (Sml2 cat.. Mg, chlorosilane) [17]. Likewise,... 

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