Oxoammonium Salts. 6.¹ 4-Acetylamino-2,2,6,6-tetramethylpiperidine-1-oxoammonium Perchlorate:  A Stable and Convenient Reagent for the Oxidation of Alcohols. Silica Gel Catalysis

Abstract

4-Acetylamino-2,2,6,6-tetramethylpiperidine-1-oxoammonium perchlorate, 1, is a stable, nonhygroscopic oxoammonium salt that is easily prepared and can be used for the oxidation of alcohols to ketones or aldehydes in near quantitative yields. The reaction is colorimetric, does not require anhydrous conditions, does not involve heavy metals, and can be carried out conveniently. Furthermore, the oxidant can be easily regenerated. The oxidation is somewhat specific in that the relative reactivities of an allyl alcohol (geraniol), benzaldehyde, and 1-decanol are about 100:1:0.1. The reaction is catalyzed by silica gel.

Nitroxide decomposition: Implications toward nitroxide design for applications in living free‐radical polymerization

“…Amines, phosphines, phenols, and anilines can also be oxidized with nitroxides. Active oxammonium salt 2 can be isolated and used as a stoichiometric oxidant with the judicious choice of a counterion, 17 or more commonly it is formed in situ from catalytic nitroxide with the aid of a primary oxidant. 12,[14][15][16]23,[94][95][96][97][98][99][100][101] Ma and Bobbitt 102 demonstrated that alcohols can be oxidized by oxammonium salts (3) generated by the acid-promoted disproportionation of excess TEMPO (Scheme 3).…”

“…These unusual properties have led to a wide range of applications spanning their use in biology as spin labels [1][2][3][4][5][6] to the development of organomagnetic materials. 7 In organic chemistry, nitroxides have been used in kinetic studies, [8][9][10][11] as oxidizing species in the form of the corresponding N-oxo ammonium salts, [12][13][14][15][16][17][18][19][20][21][22][23] as temporary caps for transient carbon radicals, [24][25][26][27][28][29][30][31] and as probes for stereocontrol with prochiral carbon radicals. [32][33][34][35][36] In polymer chemistry, nitroxide-mediated polymerization (NMP) [37][38][39][40][41][42][43][44][45][46][47] has become popular as a method for preparing living polymers ...…”

Stable 5‐Substituted Cyclopentadienes for the Diels–Alder Cycloaddition and their Application to the Synthesis of Palau'amine

“…The latter is prepared from cyclopentadiene by an easily scalable, three-step procedure involving a Prins reaction with formaldehyde, selective allylic oxidation with the reagent developed by Bobbitt, and protection of a primary alcohol. [5,6] Silyl enol ether formation from 4 may be accomplished under either soft (R 3 SiOTf, NEt 3 ) or hard (lithium diisopropylamide, R 3 SiCl) enolization reaction conditions. [7] In this way, the tert-butyldimethylsilyl (TBS), triethylsilyl, or trimethylsilyl enol ethers may be prepared, with the former being preferred because of the increased hydrolytic stability of the diene and the subsequent cycloadducts.…”

2,2,6,6-Tetramethylpiperidine-Based Oxoammonium Salts

“…1 In addition to being more sustainable, these salts have several advantages: 1) the spent oxidant is easily recovered and recyclable; 2) oxidations are performed under mild conditions and are simple to conduct; 3) oxidations are typically colorimetric processes and reaction progress can be monitored visually. 2 …”