Herein, we have described a novel N-heterocyclic carbene (NHC)-catalyzed synthesis of -substituted isoindolinone acetates. The presented transformation proceeds through NHC-catalyzed tandem imine umpolung-intramolecular aza-Michael addition followed by oxidation, while molecular oxygen in air acts as a sole oxidant. Atom efficiency, operational simplicity, large-scale syntheses, and mild reaction conditions are the salient features of this method. Mechanistic studies were indicative of the necessity of molecular oxygen in air as oxidant for the conversion of imine to amide.
The directional assembly of porous organic molecules into long-range ordered architectures, featuring controlled hierarchical porosity and oriented pore channels with defined spatial arrangements, is a fundamental challenge in chemistry and materials science. Herein, using porous organic cages as starting units, we present a cooperative multiscale-assembly strategy enabling the simultaneous alignment of pore channels and directional hierarchical growth in a single step. At the microscopic level, we employed double solvents to manipulate the intermolecular packing of microporous tetrahedral [4+6] imine cages (CC1 and CC3), resulting in pore channel orientation.
The β-lactam scaffolds are the prevalent structural units in antibiotics and natural products. Herein, three-component asymmetric Kinugasa/aldol and Kinugasa/Mannich cascade reactions have been developed for constructing α-quaternary chiral β-lactams. This method involved the tandem reaction of alkynes, nitrones and aldehydes (or imines), resulting in the formation of three sequential stereocenters controlled by copper(I) catalysts and chiral bis(oxazolidine) ligands.
State Key Laboratory of Chemical Resource Engineering, Department of Organic Chemistry, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China.
Various -1,2,4-trihydrobenzo[][1,2]azaphosphinine 3-oxides are synthesized highly stereoselectively from generated phosphenes and formaldimines under microwave irradiation. Aryl(diazo)methyl(diaryl)phosphine oxides first undergo the Wolff rearrangement to generate phosphenes. Imines, generated from 1,3,5-triazinanes or paraformaldehyde and primary amines, nucleophilically attack the phosphenes followed by a tandem stereoelectronic effect-controlled intramolecular nucleophilic addition and aromatization to give final -1,2,4-trihydrobenzo[][1,2]azaphosphinine 3-oxides, exhibiting completely different annuloselectivity from linear nonformaldimines.
Saturated heterocycles are important for drug development but are difficult to synthesize, especially in an asymmetric manner.*
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The study illustrates the use of imine reductases in tandem processes to create these heterocycles through both inter- and intramolecular reductive amination.*
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The approach enables the production of various unsubstituted and substituted heterocycles from simple materials in a single reaction under mild conditions, showcasing the versatility of imine reductases.*
Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo, São Paulo 05508-000, Brazil.
Bisbenzoxazines () are a relevant model for the diverse bifunctional benzoxazines that are used to increase the polybenzoxazines cross-linking extensions and modulate the final resin properties for various usages. The presence of side products and intermediates during monomer formation can influence the resin characteristics by inducing chain termination and ramifications, affecting the polymerization and cure processes. This work investigated the diverse isomeric intermediates and side products that are present during the formation from bisphenol A, aniline, and formaldehyde by ion mobility coupled to mass spectrometry (MS/MS) and ion spectroscopy techniques.
