The O-H Insertion of Sulfonic Acids with Mono-and Di-Substituted Diazo Compounds under Catalyst-Free Neat Condition

We report a novel, catalyst-free protocol for the synthesis of sulfonate esters from acceptor, acceptor-acceptor and donor-acceptor substituted diazo compounds and various sulfonic acids. Because of the operational simplicity under solvent free condition, it is a significant addition to the existing techniques for the access of sulfonate esters. This practical and green approach works well with a wide range of substrates.