Organic oxoammonium salts. 3. A new convenient method for the oxidation of alcohols to aldehydes and ketones

Abstract

A new method for the selective oxidation of alcohols using organic oxoammonium salta generated by acidpromoted disproportionation of nitroxides in solution has been developed. Major advantages are high yields, ease of product isolation, and a high degree of selectivity in the presence of other functional groups.

Synthesis of 2-amino alcohols and unnatural amino acids from serine

“…17,18 N-Protected α-aminoaldehydes may be prepared either by reduction of a carboxy derivative of an amino acid or by oxidation of 2-aminoalcohols, and it is known that they have a high tendency for racemization. 19 The NaOCl/TEMPO method was chosen because it appears superior to reductive methods in terms of preservation of the enantiomeric purity.…”

Synthesis and properties of dinitrobenzamido-TEMPO derivatives

“…Oxidizing properties of TEMPO radicals are known, [20][21][22] and such compounds may be used for mild oxidations of thiols, amines, primary or secondary alcohols, It is also known that in acidic medium TEMPO derivatives 10 undergo disproportionation yielding oxoammonium (11) and hydroxylamine salts (12), as indicated in Scheme 4. Compounds 3a,b-7a were tested as oxidants for compounds 13a-13f 23,24 in the absence (no reaction) and in the presence of para-toluenesulfonic acid 21 (when the blue-violet betainic structures 14a-14f occurred).…”

“…Compounds 3a,b-7a were tested as oxidants for compounds 13a-13f 23,24 in the absence (no reaction) and in the presence of para-toluenesulfonic acid 21 (when the blue-violet betainic structures 14a-14f occurred). 23,24 In the reaction with 2,2-diphenyl-1-picrylhydrazine (DPPHine, 15, R = H), compounds 3a,b and 5a,b afforded in the presence of para-toluenesulfonic acid the violet 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH) (16, R = H), together with traces of its nitro-derivative (16, R = NO 2 ).…”

Utilização do TEMPO (N-oxil-2,2,6,6-tetrametilpiperidina) na oxidação de álcoois primários e secundários

“…Uma proposta mecanística razoável segundo Semelhack seria a formação do intermediário 8 via uma reação de eliminação intramolecular (Figura 3), embora existam algumas evidências de que o intermediário 9 poderia também ocorrer. Ma e Bobbit 23 propuseram também o aduto 10, que forneceria o produto oxidado via uma reação de eliminação (Figura 3).…”