PhI(OAc)2-promoted umpolung acetoxylation of enamides for the synthesis of α-acetoxy ketones

Manganese-Catalyzed Desaturation of N-Acyl Amines and Ethers

“…26,44−47 Also, PhI(OAc) 2 is known to react with enamines. 48 Thus, we were curious as to why the desaturated products could be isolated in such high yields. Interestingly, when a reaction mixture with the N-benzoyl substrate 1c was examined by mass spectrometry, a hydroxylated product (presumably the hemiaminal) was observed (see Supporting Information).…”

CBr4 Promoted α‐Acyloxyation of β‐Keto Esters and β‐Diketones by Sodium Carboxylates

“…The oxidative coupling of ketones with carboxylic acids was catalyzed by hypervalent iodine agents which was generated in situ. In recent years, several new metal‐free synthetic methods [4] including the oxidative coupling of ketones with aldehydes [5] , benzylic alcohols [6] , toluene [7] , alkenes [8] , or acyl peroxides [9] , the umpolung acetoxylation [10] or intramolecular acyl migration [11] of enamides have been reported to realize this intermolecular C−O bond coupling.…”

Synthesis of α‐Acyloxy‐α′‐hydroxy Ketones via Cyclic Carbonate Intermediates Generated from Tertiary Bromopropargylic Alcohols and Cs2CO3

“…The methods for α‐acyloxy ketone synthesis are α‐acyloxylation of functionalized carbonyl compounds (α‐haloketones, α‐diazoketones) with an alkaline carboxylates or carboxylic acids, the direct oxidative coupling of ketones with carboxylic acids,[7c], oxo‐acyloxylation of the alkenes,[7c], Ru‐catalyzed addition of carboxylic acids to propargylic alcohol. [7c], Also, there have been developed alternative methods: NBS/DBU mediated α‐acyloxylation of benzylic secondary alcohols with carboxylic acids, the transformation of enamides through an intramolecular oxidative acetyl migration process mediated by hydrogen peroxide and acetic anhydride, PhI(OAc) 2 ‐promoted umpolung acetoxylation of enamides, Yb(OTf) 3 ‐catalyzed oxidative decarboxylation of β‐keto acids mediated by (diacetoxyiodo)benzene and carboxylic acids, self‐intermolecular oxidative coupling of aryl ketones using I 2 /TBHP and I 2 /TBHP‐mediated α‐benzoyloxylation of ketones, a HI‐promoted di‐deiodination of α′‐acetoxy‐α,α‐dihaloketones …”