Sulfonylimination of Proline with Sulfonylazides Involving Aldehyde-Induced Decarboxylation Coupling.

In the presence of aldehyde, a facile method was developed to obtain N-sulfonyl amidines under metal- and oxidant-free conditions by the decarboxylative of proline. This transformation features a double C-N bond formation and allows for the green synthesis of the N-sulfonyl amidines on the basis of mild conditions.