Air‐Induced One‐Pot Synthesis of N‐Sulfonylformamidines from Sulfonyl Chlorides, NaN₃, and Tertiary/Secondary Amines

Abstract

An efficient and practical one‐pot strategy for the synthesis of N‐sulfonylformamidines was developed by directly using easily available sulfonyl chlorides, sodium azide and tertiary/secondary amines in the presence of 5 mol‐% CuBr2 under aerobic oxidative conditions.

Transition metal- and catalyst-free one-pot green method for the synthesis of N-sulfonyl amidines via direct reaction of sulfonyl azides with amines

“…In the past years, various methods have been developed for the synthesis of N-sulfonyl amidines. [13][14][15][16][17][18][19][20][21] These include: (a) condensation of amides with sulfonylamides, 13,14 (b) Cucatalyzed three-component coupling reactions of sulfonyl azides, alkynes and secondary amines, 15 (c) Pd-catalyzed carbonylation/coupling of sulfonylazides and substituted amides, 16 and (d) cross-coupling reaction of sulfonyl azides with tertiary amines [17][18][19][20][21] (Scheme 1). Among them, cross-coupling of sulfonyl azides with tertiary amines has attracted much more attention.…”

“…Among them, cross-coupling of sulfonyl azides with tertiary amines has attracted much more attention. The key intermediate is enamine generated by oxidative dehydrogenation of amines in the presence of CuBr 2 , 17 CuCl/CCl 4 , 18 or FeCl 3 . 19 On the other hand, Li and co-workers reported the cascade reaction of tertiary amines with sulfonyl azides in the presence of DEAD (diethyl azodicarboxylate) for the preparation of N-sulfonyl amidines.…”

Copper-Catalyzed Coupling of Sulfonamides with Alkylamines: Synthesis of (E)-N-Sulfonylformamidines

“…Other synthetic approaches to construct N -sulfonylamidines were also developed . In addition, methods through direct coupling between sulfonyl azides and tertiary amines to construct N -sulfonylformamidines were also reported (Scheme c) . In addition, direct condensation of sulfonamides with alkynes and amines (Scheme d) or with amides (Scheme e) to synthesize N -sulfonylamidines has also been disclosed.…”

“…In addition, direct condensation of sulfonamides with alkynes and amines (Scheme d) or with amides (Scheme e) to synthesize N -sulfonylamidines has also been disclosed. However, these reported protocols suffer from conditions using explosive organic azide, − or corrosive coupling reagents . In some cases, only a limited substrate scope has been demonstrated.…”

Catalyst-free one-pot, four-component approach for the synthesis of di- and tri-substitutedN-sulfonyl formamidines

“…Another recently reported Cu-catalyzed three-component approach employed sulfonyl chlorides, sodium azides, and amines ( Scheme 1b ). 11 Additionally, Bi and co-workers 12 described a silver-catalyzed, one-pot, four-component reaction involving terminal alkynes reacting directly with trimethylsilyl azide (TMSN 3 ), sodium sulfinate, and sulfonyl azide ( Scheme 1c ). Phukan et al 13 described a metal-free strategy for the synthesis of di-substituted sulfonyl amidines via a one-pot reaction between tert -butylisonitrile and N , N -dibromoaryl sulfonamides in the presence of a nitrile compound in aqueous media ( Scheme 1d ), and other groups have applied similar methods.…”