Acyl-Ethynylbenziodoxolone (acyl-EBX): Access to Ketene Dithioarylacetals.

We report the synthesis of ketene dithioarylacetals in 40-97% yield using thiophenols and acyl-EBXs (ethynylbenziodoxolones) generated in situ from a common hypervalent iodine precursor and alkynyl trifluoroborate salts. The products could be further modified to afford functionalized ketene dithioacetals and various S-substituted heterocycles.

Iron-Catalyzed Synthesis of α-Azido α-Amino Esters via the Alkylazidation of Alkenes.

An iron-catalyzed alkylazidation of dehydroamino acids using peroxides as alkyl radical precursors is described. Non-natural azidated amino esters bearing an α-alkyl chain could be obtained in 18-94% yields using TMSN3 as an azide source. The obtained α-alkyl-α-azide α-amino esters could be further functionalized through cycloaddition or azide reduction with amide couplings to afford aminal-type peptides, α-triazolo amino acids, and tetrahydro-triazolopyridine, showing the great versatility of this now easily accessible class of amino acids.

Palladium-Catalyzed Synthesis of Bis-Substituted Sulfoxonium Ylides.

The lack of general access to bis-substituted sulfoxonium ylides is addressed by developing a palladium-catalyzed C-H cross-coupling of α-ester sulfoxonium ylides with (hetero)aryl iodides, bromides, and triflates. Three different catalysts have been evaluated. This method is amenable to the late-stage functionalization of active pharmaceutical ingredients.