Synthesis of acyloxy-2-azirine and sulfonyloxy-2-azirine derivatives a one-pot reaction of β-enamino esters, PIDA and carboxylic acid or sulfonic acid.

PIDA mediated oxidative acyloxylation/azirination and sulfonyloxylation/azirination of β-enamino esters were investigated. A series of functionalized acyloxy-2-azirine and sulfonyloxy-2-azirine derivatives was synthesized in moderate to good yields. This represents the first oxidative sulfonyloxylation/azirination of β-enamino esters with PIDA and sulfonic acid for access to sulfonyloxy-2-azirine. Hypervalent iodine reagents enable cascade C-O/C-N bond formation. Furthermore, a possible reaction pathway was proposed based on the experimental results.