Flashcard library · Chemistry · PaperFren
Catalytic Mitsunobu chemistry with recyclable azo reagents
Ethyl arylazocarboxylates plus iron phthalocyanine and air replace stoichiometric DEAD in Mitsunobu esterifications with high inversion.
Keep what you just learned
Save these 11 cards to your NoteFren library. Your first review starts right away, and each card links back to the study it came from.
What waste problem does catalytic Mitsunobu attack?
Stoichiometric DEAD/PPh3 make hydrazine and phosphine oxide waste; DEAD is toxic/explosive.
Source: Advances and mechanistic insight on the catalytic Mitsunobu reaction using recyclable azo reagents · DOI · quote verified
How is the azo catalyst recycled?
Aerobic re-oxidation of the hydrazine with iron phthalocyanine.
Source: Advances and mechanistic insight on the catalytic Mitsunobu reaction using recyclable azo reagents · DOI · quote verified
Which catalyst is best for carboxylic acids/inversion?
Ethyl 2-(3,4-dichlorophenyl)hydrazinecarboxylate (1a).
Source: Advances and mechanistic insight on the catalytic Mitsunobu reaction using recyclable azo reagents · DOI · quote verified
Which catalyst is highlighted for other nucleophiles?
Ethyl 2-(4-cyanophenyl)hydrazinecarboxylate (1j).
Source: Advances and mechanistic insight on the catalytic Mitsunobu reaction using recyclable azo reagents · DOI · quote verified
What did hot THF give for model ester 5?
50% yield and 97% inversion.
Source: Advances and mechanistic insight on the catalytic Mitsunobu reaction using recyclable azo reagents · DOI · quote verified
What did toluene at room temperature give?
88% yield and a perfect inversion ratio.
Source: Advances and mechanistic insight on the catalytic Mitsunobu reaction using recyclable azo reagents · DOI · quote verified
Why are molecular sieves required?
The azo/PPh3 intermediate is highly moisture sensitive; no reaction without sieves.
Source: Advances and mechanistic insight on the catalytic Mitsunobu reaction using recyclable azo reagents · DOI · quote verified
What sieve activation gave 94% yield?
Flame heating under reduced pressure.
Source: Advances and mechanistic insight on the catalytic Mitsunobu reaction using recyclable azo reagents · DOI · quote verified
Does concentration help?
Yes: 2.0 M or 4.0 M improved yields of 5.
Source: Advances and mechanistic insight on the catalytic Mitsunobu reaction using recyclable azo reagents · DOI · quote verified
What green-chemistry oxidant is emphasized?
Atmospheric oxygen as sacrificial oxidant to regenerate the azo form.
Source: Advances and mechanistic insight on the catalytic Mitsunobu reaction using recyclable azo reagents · DOI · quote verified
Do chlorinated solvents preserve inversion?
They can give good yield but a low inversion ratio.
Source: Advances and mechanistic insight on the catalytic Mitsunobu reaction using recyclable azo reagents · DOI · quote verified