Sulfonamides trapping reagents

C.viii. Amines, Amides, Imides, and Sulfonamides as the H—Y Trapping Reagents Intermolecular Diene Dimerization... 

Scheme 3.48. Sulfonamide/CuX-catalyzed addition of dialkylzinc reagents to 2-enones and subsequent trapping of the zinc enolates [199a-bj.

Sulfonyl azides participate in unique CuAAC reactions with terminal alkynes. Depending on the conditions and reagents, products other than the expected triazole 20 [118] can be obtained, as shown in Scheme 7.9. For example, N-sulfonyl azides are converted to N-sulfonyl amidines 21 when the reaction is conducted in the presence of amines [119]. In the aqueous conditions, N-acyl sulfonamides 22 are the major products [120,121]. In addition to amines and water, the latter can be trapped with imines, furnishing N-sulfonyl azetidinimines 23 [122]. 

---