N‐Cyanation of Primary and Secondary Amines with Cyanobenzio‐doxolone (CBX) Reagent

Abstract

An efficient electrophilic N-cyanation of amines with a stable and less-toxic cyanobenziodoxole reagent towards the synthesis of cyanamides is disclosed. This synthetically practicable strategy allows the construction of a wide variety of cyanamides under very mild and simple conditions with a broad functional group compatibility, and showcases a huge potential in late-stage modification of complex molecules.

Synthesis of Carbamoyl Fluorides Using a Difluorophosgene Surrogate Derived from Difluorocarbene and Pyridine N-Oxides

“…The colorless oil (0.106 g, 0.73 mmol, 66%) was isolated after purification by flash column chromatography: 25% EtOAc in hexanes. The spectral data are consistent with literature values …”

“…The spectral data are consistent with literature values. 62 N-But-3-ynylaniline (1af). The title compound was synthesized by stirring aniline (0.44 mL, 4.86 mmol), but-3-ynyl 4-methylbenzenesulfonate (0.727 g, 3.24 mmol), potassium iodide (0.057 g, 0.32 mmol), and K 2 CO 3 (1.344 g, 9.72 mmol) in DMF at 90 °C for 16 h. The reaction was diluted with water and extracted 3× with Et 2 O.…”

Recent Progress in Synthetic Applications of Cyclic Hypervalent Iodine(III) Reagents

“…For example, the reaction of reagent 32 with primary or secondary amines 48 proceeds quickly and efficiently to give N ‐cyanated products 49 in moderate to high yield (Scheme 19). [74] This reaction does not affect double or triple bonds, as well as ester and ketone functional groups. In the presence of an alcohol group in the molecule, reagent 32 selectively reacts with the nitrogen atom to give the corresponding product 49 .…”

“…Cyanobenziodoxole reagents can be used to perform cyanation reactions at heteroatoms, such as nitrogen, [74][75] oxygen, [76] and sulfur, [77] as well as carbon. For example, the reaction of reagent 32 with primary or secondary amines 48 proceeds quickly and efficiently to give N-cyanated products 49 in moderate to high yield (Scheme 19).…”

Hypervalent Iodine‐Mediated Azidation Reactions

“…It is known that the cyclic or pseudocyclic hypervalent iodine compounds, known under the general name of benziodoxoles, are characterized by enhanced stability, which is explained by the lower reactivity of hypervalent iodine center toward reductive elimination because of the link between apical and equatorial positions via the five‐membered ring [63] . Such a stabilization of hypervalent iodine in a cyclic system made possible the preparation of several important, stable benziodoxole‐derived reagents, including trifluromethylbenziodoxole (Togni reagent), [64] ethynylbenziodoxole, [65] vinylbenziodoxoles, [66] cyanobenziodoxoles, [65,67] and azidobenziodoxole [8j] . These stable benziodoxoles are known under the general name of “atom‐transfer” reagents [68] …”