Expedient Immobilization of TEMPO by Copper‐Catalyzed Azide‐Alkyne [3+2]‐Cycloaddition onto Polystyrene Resin

Gheorghe, Alexandru; Matsuno, Ai; Reiser, Oliver

doi:10.1002/adsc.200606043

Cited by 112 publications

(48 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Size exclusion chromatography confirmed the efficiency of these consecutive decoupling, nitroxide exchange, and CuAAC reactions. [22] TEMPO-≡ was synthesized following the previously described method by Reiser et al [23] Synthesis 4-Hydroxy-2,2,6,6-tetramethylpiperidin-1-yloxyl (TEMPO-OH) (Fig. 6) [6] To a solution of 2,2,6,6-tetramethyl-4-piperidinol (5.00 g, 31.8 mmol) in MeOH (59.2 mL) was added NaHCO 3 (2.…”

Section: Resultsmentioning

confidence: 99%

Ultrafast and Reversible Multiblock Formation by the SET-Nitroxide Radical Coupling Reaction

et al. 2010

View full text Add to dashboard Cite

The single electron transfer-nitroxide radical coupling (SET-NRC) reaction has been used to produce multiblock polymers with high molecular weights in under 3 min at 50 • C by coupling a difunctional telechelic polystyrene (Br-PSTY-Br) with a dinitroxide. The well known combination of dimethyl sulfoxide as solvent and Me 6 TREN as ligand facilitated the in situ disproportionation of Cu I Br to the highly active nascent Cu 0 species. This SET reaction allowed polymeric radicals to be rapidly formed from their corresponding halide end-groups. Trapping of these carbon-centred radicals at close to diffusion controlled rates by dinitroxides resulted in high-molecular-weight multiblock polymers. Our results showed that the disproportionation of Cu I was critical in obtaining these ultrafast reactions, and confirmed that activation was primarily through Cu 0 . We took advantage of the reversibility of the NRC reaction at elevated temperatures to decouple the multiblock back to the original PSTY building block through capping the chain-ends with mono-functional nitroxides. These alkoxyamine end-groups were further exchanged with an alkyne mono-functional nitroxide (TEMPO-≡) and 'clicked' by a Cu I -catalyzed azide/alkyne cycloaddition (CuAAC) reaction with N 3 -PSTY-N 3 to reform the multiblocks. This final 'click' reaction, even after the consecutive decoupling and nitroxide-exchange reactions, still produced highmolecular-weight multiblocks efficiently. These SET-NRC reactions would have ideal applications in re-usable plastics and possibly as self-healing materials.

show abstract

Section: Resultsmentioning

confidence: 99%

Ultrafast and Reversible Multiblock Formation by the SET-Nitroxide Radical Coupling Reaction

et al. 2010

View full text Add to dashboard Cite

show abstract

“…Azide-functionalized AO resin (AO-N 3 , 2 ) was prepared by treating AO with sodium azide (Scheme 1) [41]. The coupling of 4-hydroxy-TEMPO 3 with propargyl bromide ( 4 ) using sodium hydride yielded the acetylene-modified TEMPO species 5 [33–34 37]. TEMPO derivative 5 was then covalently bound to AO-N 3 using copper(I) iodide [42–45], yielding the TEMPO-functionalized resin (AO-TEMPO, 6 , Scheme 2, 0.46 mmol TEMPO/g resin).…”

Section: Resultsmentioning

confidence: 99%

A biphasic oxidation of alcohols to aldehydes and ketones using a simplified packed-bed microreactor

Bogdan¹,

McQuade²

2009

Beilstein J. Org. Chem.

View full text Add to dashboard Cite

SummaryWe demonstrate the preparation and characterization of a simplified packed-bed microreactor using an immobilized TEMPO catalyst shown to oxidize primary and secondary alcohols via the biphasic Anelli-Montanari protocol. Oxidations occurred in high yields with great stability over time. We observed that plugs of aqueous oxidant and organic alcohol entered the reactor as plugs but merged into an emulsion on the packed-bed. The emulsion coalesced into larger plugs upon exiting the reactor, leaving the organic product separate from the aqueous by-products. Furthermore, the microreactor oxidized a wide range of alcohols and remained active in excess of 100 trials without showing any loss of catalytic activity.

show abstract

“…The immobilization of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) on a variety of organic supports [1,2,9,[14][15][16][17][18][19][20][21][22][23], inorganic supports [4,7,12,[24][25][26][27][28][29][30] and ionic liquids confined in the pore system of inorganic supports [31][32][33][34] has been widely described.…”

Section: Introductionmentioning

confidence: 99%

New method for the immobilization of nitroxyl radical on mesoporous silica

Machado

Casimiro

Ferreira³

et al. 2015

Microporous and Mesoporous Materials

View full text Add to dashboard Cite

a b s t r a c tThis work reports the covalent attachment of 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (4-hydroxy-TEMPO) on the mesoporous silicas MCM-41 and SBA-15, by using 1,4-diisocyanatobutane as a binder. The catalysts were characterized by nitrogen adsorption/desorption, XRD, TEM, TGA, DSC and FTIR spectroscopy. Catalytic tests were performed on the liquid phase oxidation of benzyl alcohol and the secondary alcohol isoborneol by using tert-butyl hydroperoxide as oxidant. The catalysts showed good activity and stability in consecutive oxidation experiments with the same catalyst samples.

show abstract

Expedient Immobilization of TEMPO by Copper‐Catalyzed Azide‐Alkyne [3+2]‐Cycloaddition onto Polystyrene Resin

Cited by 112 publications

References 52 publications

Ultrafast and Reversible Multiblock Formation by the SET-Nitroxide Radical Coupling Reaction

Ultrafast and Reversible Multiblock Formation by the SET-Nitroxide Radical Coupling Reaction

A biphasic oxidation of alcohols to aldehydes and ketones using a simplified packed-bed microreactor

New method for the immobilization of nitroxyl radical on mesoporous silica

Contact Info

Product

Resources

About