Advances in the Synthesis of N-Sulfonyl Amidines

Abstract

Due to the special gem-nitrogen structure, amidines are important compounds in the synthesis of nitrogen contaning products. As a class of featured amidines, the N-sulfonyl amidines are key intermediates in a number of pivatol organic syntheses, and thus ocuppy significant position in modern organic synthesis. In this context, the research advances on the synthesis of N-sulfonyl amidines are herein reviewed. Based on the key reaction features, the introduction covers the synthetic methods of enamination by tertiary enamine oxidation, amide activation, akyne-azide-amine three-component reaction, enamine carbon-carbon bond functionalization and other related reactions. It is expected that this review will provide guidelines for the reasearch work in related areas.

Recent Advances in Reactions Using Enaminone in Water or Aqueous Medium

“…Rather recently, our continuous explore [21] in such annulation reactions proved that enaminoesters 23 (R 3 =aryl) could react with tosyl azide in pure water medium to access 1,2,3‐triazoles 24 in the presence of catalytic amount of Et 3 N. In addition, when N ‐alkyl enaminoesters of type 23 was used, the selectivity of the reaction was switched to provide sulfonamides 25 (Scheme 11). Control experiment in water using directly β‐keto ester and primary amine as precursors of 23 to react with 19 did not provide product 24 , confirming that the interaction of enaminone and water was crucial for the reactions.…”

Modular Synthesis of Enantioenriched α-Chiral Homoallylic Amidines Enabled by Relay Ir/Cu Catalysis

“…5 Over the past few decades, tremendous effort has been devoted to exploiting approaches to access amidines from readily available starting materials, e.g., amides, enamines, alkynes, and so on. 6 However, few asymmetric methods were developed toward the synthesis of enantioenriched α-branched amidines,despite their importance in organic synthesis. Currently, the asymmetric α-alkylation reaction of aliphatic amidines represents a general strategy for constructing chiral amidines (Scheme 1a).…”

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

“… 5 Over the past decade, research regarding the formation of N -sulfonyl amidines has led to remarkable progress. 6 …”

“…Therefore, the development of an efficient and practical method for the synthesis of N -sulfonylamidine derivatives is critical. Although tri-substituted sulfonyl(form)amidines have been widely explored, 6 a – r the synthesis of di-substituted N -sulfonyl formamidines is rare in the literature; to our knowledge, only one research paper (from Jacobson and co-workers, 1977) 15 has described the synthesis of N , N ′-di-substituted sulfonyl formamidines using sulfonamide and isocyanides in the presence of a copper catalyst.…”