Research and Application of N-Ts Cyanamides in Organic Synthesis

Abstract

N-Ts cyanamide, which has been widely used in the construction of nitrogen-containing framework, is one of the efficient and practical multifunctional synthetic precursors in organic synthesis. The progress in application of N-Ts cyanamide according to the reaction types is summarized, including the application in cyanation, cyclization reaction via cyanamide anion, cyanamidation, sulfonylation and cyclization reaction via cyano-group. The future development direction of this field is also prospected.

Generation and application of carbodiimide anions: efficient construction of 2-aminopyrimidines via a cascade [4 + 2] annulation/aromatization sequence

“…4,5 Recently, our group developed two practical methods for synthesizing five-membered cyclic guanidines G–I , employing the cascade [3 + 2] annulations of cyanamide anions with aziridines and α-haloamides. 6 However, N-Ts cyanamide involved [4 + 2] annulations (Scheme 1, part II, path b) and carbodiimide anion participated annulations (Scheme 1, part II, path c) have not yet been disclosed. Hence, the studies on regulating N-Ts cyanamides to participate in reactions selectively via carbodiimide anions C and expanding their application in [4 + 2] annulations are significant.…”

Cu‐Catalyzed Site‐ and Enantioselective Borylcyanation of 1,2‐Disubstituted Aryl Alkenes

“…Introduction of a cyano group into organic molecule is highly desirable due to its wide existence in biologically active molecules and ease for further transformations to other functional groups [8] . Although pioneering works on site selective cyanation of organocopper intermediates generated from Cu−B(pin) addition to terminal alkenes, 1,3‐dienes or allenes have been reported by Buchwald, [7a] Montgomery, [7b–c] Fu, [7d] Procter, [5b,7e] Liu [7h] and our group [7f] (Scheme 1a–c), Cu‐catalytic enantioselective borylcyanation reactions of 1,2‐disubstituted alkenes remains unknown (Scheme 1d) [9] . The challenges for such transformations include: (1) the reactions have to be performed at elevated temperature, so it is not trivial to achieve high enantioselectivity; (2) the chiral Cu complex has to induce high enantioselectivity of Cu−B(pin) addition, and the same catalyst has to control the site selectivity of the resulting secondary benzyl‐Cu complex I (Scheme 1d).…”

“…[8] Although pioneering works on site selective cyanation of organocopper intermediates generated from CuÀ B(pin) addition to terminal alkenes, 1,3-dienes or allenes have been reported by Buchwald, [7a] Montgomery, [7b-c] Fu, [7d] Procter, [5b,7e] Liu [7h] and our group [7f] (Scheme 1a-c), Cu-catalytic enantioselective borylcyanation reactions of 1,2-disubstituted alkenes remains unknown (Scheme 1d). [9] The challenges for such transformations include:…”