1.9.2.1 Oxidation of Alcohols

TEMPO is a mild catalyst for the oxidation of alcohols to give carbonyl compounds (Scheme 4). NaOCl is usually used as a co-oxidant for the regeneration of the catalyst. The reactions with primary alcohols exhibit greater reactivity compared to secondary alcohols. Thus, primary alcohols could be chemoselectively oxidized in the presence of secondary alcohols.  

Scheme 4

 

Mechanism
The oxidation of nitroxyl radical gives the oxoammonium ion, which is the active species, in the TEMPO catalyzed reactions (Scheme 4).

Scheme 5

Examples:

K. Sakuratani, H. Toga, synthesis 2003, 21.

J. B. Epp, T. S. Widlanski, J. Org. Chem. 1999, 64, 293.

L. D. Luca, G. Giacomelli, A. Porcheddu, Org. Lett. 2001, 3, 3041.