Application of DMF-methyl sulfate adduct in the regioselective synthesis of 3-acylated indolizines

A number of 3-acylated indolizines were synthesized in good to excellent yields by a newly established reaction between picolinium salts and the methylsulfate salt of A (R = Me), the adduct formed from DMF-Me₂SO₄ as the key reagent. The low cost, short reaction time, mild reaction condition, and easy purification of the products make this an attractive new method for the synthesis of indolizine compounds. A variety of functional groups (nitro, cyano, ester, methoxy, and halogens) were well tolerated under the reaction conditions.