Silver-Mediated Direct C–H Cyanation of Terminal Alkynes with N -Isocyanoiminotriphenylphosphorane

Zhao

et al. 2019

Eur J Org Chem

A direct synthesis of azines from the silver catalyzed domino interaction of N-isocyaniminotriphenylphosphorane and aldehydes is reported. The reaction proceeds through a tandem aza-Wittig, insertion, intramolecular cyclization and [a] Typical Synthetic Procedure (with 3a as an example): To a dried Schlenk flask N-Isocyanoiminotriphenylphosphorane 1 (604 mg, 2.0 mmol), 4-chlorobenzaldehyde 2a (70.3 mg, 0.5 mmol) and Ag 2 CO 3 (27.5 mg, 0.10 mmol) were added under air atmosphere. After evacuated and refilled with nitrogen 3 times, 1,4-dioxane (4 mL), DIPEA (41.3 μL, 0.25 mmol) and BF 3 ·Et 2 O (18.5 μL, 0.15 mmol) was added in one portion to the mixture by syringe. The mixture was stirred at 100°C for 12 h until substrate 2a disappeared. After completion, the resulting mixture was concentrated and extract with diethyl ether (3 × 15 mL), washed with brine (3 × Eur.7239 40 mL). Then combined organic layer was dried with MgSO 4 and concentrated. Finally, the crude product was further purified by flash column chromatography and recrystallization with diethyl ether to give pure product 3a as a yellow solid in 77 % yield.

Section: Introductionmentioning

confidence: 91%

Silver‐Catalyzed Cascade Reaction of N‐Isocyaniminotriphenylphosphorane with Aldehydes: Synthesis of Unsymmetrical Azines

Zhao

et al. 2019

Eur J Org Chem

“…This procedure, applying NIITP as a nontoxic, facile "CN" source, was characterized by its operational simplicity, high efficiency with excellent yields, broad substrate scope, and greater functional group tolerance. 24 In addition, copper-catalyzed direct cyanation of terminal alkynes with benzoyl cyanide was reported by Li in 2018. This protocol using less toxic, stable and easy to handle benzoyl cyanide as a cyanide source and air as an oxidant provided a good alternative to the preparation of 3-arylpropiolonitriles under mild condition.…”

Section: Direct Cyanation and Hydrocyanation Of Alkynesmentioning

confidence: 99%

“…Direct cyanation reaction of terminal alkynes 7 with N-isocyanoiminotriphenylphosphorane (NIITP) in the presence of a quantitative amount of AgOTf in DMF produced propionitriles 8 in moderate to good yields (Scheme 3). 24 A plausible mechanism for this cyanation reaction was shown in Scheme 4, rstly, ethynylbenzene reacted with AgOTf to generate the silver acetylide A. Then, an acetylenic imido complex B was produced by insertion of NIITP into the silvercarbon bond of A.…”

Section: Direct Cyanation and Hydrocyanation Of Alkynesmentioning

confidence: 99%

Direct cyanation, hydrocyanation, dicyanation and cyanofunctionalization of alkynes

Peng

et al. 2020

RSC Adv.

“…[16] Bi group reported the intermolecular direct cyanation of terminal alkynes with NIITP for the synthesis of propionitrile derivatives, with the aid of silver salt using water as additive. [22] They proposed a plausible mechanism as shown in Scheme 4. The silver acetylide 14 resulted from the initial reaction of alkyne 12 with AgOTf.…”

Section: Insertion Reactionsmentioning

confidence: 99%

Progress in Reactions of N‐Isocyanoiminotriphenylphosphorane

Zhang

2020

ChemistrySelect

N‐isocyanoiminotriphenylphosphorane has been widely applied in diverse organic synthesis due to the favorable structure of isocyano neighbouring iminophosphorane. In this manuscript, we have reviewed the reactions involving N‐isocyanoiminotriphenylphosphorane including insertion reactions, cyclization reactions and multicomponent reactions in last twenty years, as well as the reaction mechanism has been illustrated clearly.