Dirhodium(II) caprolactamate: an exceptional catalyst for allylic oxidation.
The oxidation of organic molecules represents a fundamentally important chemical process. Particularly important is allylic oxidation, whereby a single methylene unit is converted directly into a carbonyl group. In this communication, we report that dirhodium(II) caprolactamate [Rh2(cap)4] in combination with tert-butyl hydroperoxide (terminal oxidant) effectively catalyzes the allylic oxidation of a variety of olefins and enones. The reaction is completely selective, tolerant of air/moisture, and can be performed with as little as 0.1 mol % catalyst in minutes. A mechanistic proposal involving redox chain catalysis has been put forth, as well as evidence for the intermediacy of a higher valent dirhodium tert-butyl peroxy complex.
Catino
Arthur J
AJ
Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA.
Forslund
Raymond E
RE
Doyle
Michael P
MP
D000498:Allyl Compounds / Q000737:chemistry*; D002209:Caprolactam / Q000031:analogs & derivatives*; D002384:Catalysis; D003516:Cycloparaffins / Q000737:chemistry*; D007659:Ketones / Q000138:chemical synthesis*; D009942:Organometallic Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D012238:Rhodium / Q000737:chemistry*
D000498:Allyl Compounds; D003516:Cycloparaffins; D007659:Ketones; D009942:Organometallic Compounds; D002209:Caprolactam; D012238:Rhodium