Autoxidation of ethyl phosphinite, phosphonite, and phosphite esters

The application of kinetic electron spin resonance spectroscopy to some reactions oft-butylperoxyl in solution

“…This is in excellent agreement with the value obtained from rates of autoxidation of toluene in the presence of E-butyl hydroperoxide [S2].F. Trivalent phosphorus compoundsTrivalent phosphorus compounds react with molecular oxygen, particularly in the presence of free-radical initiators, to give pentavalent oxygenated products[53][54][55][56]. These reactions are complex free-radical chain reactions and kinetic studies have met with limited success.…”

Cysteine‐Selective Phosphonamidate Electrophiles for Modular Protein Bioconjugations

“…[21] This issue was previously addressed by isolating air-stable borane protected phosphonites that had to be deprotected with strong bases prior SPhR. [21] This issue was previously addressed by isolating air-stable borane protected phosphonites that had to be deprotected with strong bases prior SPhR.…”

“…At the outset of our studies,w ev alidated our proposed concept by reacting readily available diethyl ethynylphosphonite with different azides containing various functional groups.Incomparison to other P III species such as phosphites, auto-oxidation of phosphonites is more rapid. [21] This issue was previously addressed by isolating air-stable borane protected phosphonites that had to be deprotected with strong bases prior SPhR. [19,20] Now,w ed eveloped ao ne-pot synthesis starting from commercially available diethyl chlorophosphite and ethynylmagnesium bromide followed by azide addition and hydrolysis without isolation of the phosphonite intermediate ( Figure 1b.W eo bserved that polar aprotic solvents generally worked best for the SPhR as they gave the best yields and ensured solubility of all tested azides.T he desired ethynylphosphonamidates 1-6 were isolated in good overall yields,with abetter performance in the formation of N-phenylphosphonamidates compared to the alkyl derivative 6.N ucleophilic functional groups such as amines,a lcohols,c arboxylic acids,a nd electrophilic NHS esters were well tolerated.…”

Cysteinselektive phosphonamidatbasierte Elektrophile für modulare Biokonjugationen

“…[19] [21] Bisher wurde dieses Problem durch die Isolierung von luftbeständigen, borangeschützten Phosphoniten gelçst, die mit Hilfe von starken Basen vor der SPhR entschützt werden mussten. [19] [21] Bisher wurde dieses Problem durch die Isolierung von luftbeständigen, borangeschützten Phosphoniten gelçst, die mit Hilfe von starken Basen vor der SPhR entschützt werden mussten.…”

“…In vorangehenden Arbeiten aus unserer Arbeitsgruppe konnten wir zeigen, dass Phosphonamidate chemoselektiv mit einer hohen Toleranz von funktionellen Gruppen in ein gegebenes azidhaltiges Protein durch die SPhR eingebaut werden kçnnen. [19] [21] Bisher wurde dieses Problem durch die Isolierung von luftbeständigen, borangeschützten Phosphoniten gelçst, die mit Hilfe von starken Basen vor der SPhR entschützt werden mussten. [19,20] Hier haben wir nun eine Eintopfreaktion ohne Isolierung des Phosphonitintermediats entwickelt, die zunächst mit der Umsetzung von handelsüblichen Diethylchlorophosphit und Ethinylmagnesiumbromid ausgeht, gefolgt von der Zugabe des Azides und Hydrolyse (Abbildung 1b).…”