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.

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.

Abstractβ‐Enaminones and β‐enaminoesters are reactive and versatile building blocks in organic synthesis. The favorable structure of electron‐withdrawing carbonyl group or ester group and electron‐donating amino groups are respectively linked at both termini of a C=C double bond. In recent years, transition metal catalyzed synthesis of β‐enaminones and β‐enaminoesters have been widely explored and continuously reported. Thus, herein we intended to review the progress in transition metal catalytic routes to these useful synthetic intermediates, with a sequence of condensation of amines with β‐dicarbonyl compounds, aldol‐type addition of ketones to nitriles, N−H olefination of amines and sulfonamides, amination of propargyl alcohols and ynones, multi‐component reactions, and other reactions.

4‐Acetylenic ketones are a class of useful and important synthons with functionalized alkynes and carbonyl groups in one molecular skeleton. They displayed unique reactivity via cyclizations that provided access to multi‐functional furans and pyrroles. This minireview offers a comprehensive coverage of the development of their multifaceted reactivity for synthetic applications in furans and pyrroles.

Pyrrole derivatives and their related five‐membered azacycles are a class of important five‐membered aromatic nitrogen heterocyclic compounds, and their synthesis attracted much the attention of organic chemists. Iron catalysis has been widely used in various organic transformations owing to their excellent catalytic activity, environmentally benign character, easy accessibility and low price. Over the past decades, a variety of facile and effective syntheses of pyrrole derivatives and related five‐membered azacycles based on iron catalysis has been reported. In this Minireview, the development of the iron‐catalyzed synthesis of pyrrole derivatives and their related five membered azacycles is reported in a comprehensive way, covering the literature up to March 2021.