Synthesis of a new fluorophore: wavelength-tunable bisbenzo[]isoindolylidenes.

The creation of new functional molecules is a central task in chemical synthesis. Herein, we report the synthesis of a new type of fluorophore, bisbenzo[]isoindolylidenes, from easily accessible dipropargyl benzenesulfonamides. Wavelength-tunable fluorophores emitting strong fluorescence of green to red light were obtained in this reaction.

Radical 1,2,3-tricarbofunctionalization of α-vinyl-β-ketoesters enabled by a carbon shift from an all-carbon quaternary center.

Herein, we report an intermolecular, radical 1,2,3-tricarbofunctionalization of α-vinyl-β-ketoesters to achieve the goal of building molecular complexity the one-pot multifunctionalization of alkenes. This reaction allows the expansion of the carbon ring by a carbon shift from an all-carbon quaternary center, and enables further C-C bond formation on the tertiary carbon intermediate with the aim of reconstructing a new all-carbon quaternary center. The good functional group compatibility ensures diverse synthetic transformations of this method.

Synthesis of unsymmetrically tetrasubstituted pyrroles and studies of AIEE in pyrrolo[1,2-]pyrimidine derivatives.

Pyrroles are among the most important heterocycles in pharmaceuticals and agrochemicals. Construction of pyrrole scaffolds with different substituents and a free NH group, however, is challenging. Herein, a metal-free method for the synthesis of unsymmetrically tetrasubstituted NH-pyrroles using a consecutive chemoselective double cyanation is reported.

Copper-Catalyzed Radical Enantioselective Carbo-Esterification of Styrenes Enabled by a Perfluoroalkylated-PyBox Ligand.

Chiral lactones are found in many natural products. The reaction of simple alkenes with iodoacetic acid is a powerful method to build lactones, but the enantioselective version of this reaction has not been implemented to date. Herein, we report the efficient catalytic radical enantioselective carbo-esterification of styrenes enabled by a newly developed Cu -perfluoroalkylated PyBox system.

Direct synthesis of pentasubstituted pyrroles and hexasubstituted pyrrolines from propargyl sulfonylamides and allenamides.

Multisubstituted pyrroles are important fragments that appear in many bioactive small molecule scaffolds. Efficient synthesis of multisubstituted pyrroles with different substituents from easily accessible starting materials is challenging. Herein, we describe a metal-free method for the preparation of pentasubstituted pyrroles and hexasubstituted pyrrolines with different substituents and a free amino group by a base-promoted cascade addition-cyclization of propargylamides or allenamides with trimethylsilyl cyanide.

Regioselective Three-Component Synthesis of Vicinal Diamines via 1,2-Diamination of Styrenes.

The vicinal diamine motif plays a significant role in natural products, drug design, and organic synthesis, and development of synthetic methods for the synthesis of diamines is a long-standing interest. Herein, we report a regioselective intermolecular three-component vicinal diamination of styrenes with acetonitrile and azodicarboxylates. The diamination products can be produced in moderate to excellent yields via the Ritter reaction.

Copper-Catalyzed Enantioselective Radical 1,4-Difunctionalization of 1,3-Enynes.

Chiral allenes are important structural motifs frequently found in natural products, pharmaceuticals, and other organic compounds. Asymmetric 1,4-difunctionalization of 1,3-enynes is a promising strategy to construct axial chirality and produce substituted chiral allenes from achiral substrates. However, the previous state of the art in 1,4-difunctionalization of 1,3-enynes focused on the allenyl anion pathway.

1,4-Fluoroamination of 1,3-Enynes en Route to Fluorinated Allenes.

The regioselective synthesis of fluorinated allenes via a metal-free 1,4-fluoroamination of 1,3-enynes is presented. This method employs commercially available -fluorobenzenesulfonimide serving as both the nitrogen source and the fluorine source, affording access to various tetrasubstituted allenes in a straightforward and atom-economic pathway. Preliminary mechanistic studies and theoretical studies revealed that this reaction might undergo an intimate ion-pair mechanism.

Revealing the Iron-Catalyzed β-Methyl Scission of -Butoxyl Radicals via the Mechanistic Studies of Carboazidation of Alkenes.

We describe here a mechanistic study of the iron-catalyzed carboazidation of alkenes involving an intriguing metal-assisted β-methyl scission process. Although t-BuO radical has frequently been observed in experiments, the β-methyl scission from a t-BuO radical into a methyl radical and acetone is still broadly believed to be thermodynamically spontaneous and difficult to control. An iron-catalyzed β-methyl scission of t-BuO is investigated in this work.

The Introduction of the Radical Cascade Reaction into Polymer Chemistry: A One-Step Strategy for Synchronized Polymerization and Modification.

Polymerization and modification play central roles in polymer chemistry and are generally implemented in two steps, which suffer from the time-consuming two-step strategy and present considerable challenge for complete modification. By introducing the radical cascade reaction (RCR) into polymer chemistry, a one-step strategy is demonstrated to achieve synchronized polymerization and complete modification in situ. Attributed to the cascade feature of iron-catalyzed three-component alkene carboazidation RCR exhibiting carbon-carbon bond formation and carbon-azide bond formation with extremely high efficiency and selectivity in one step, radical cascade polymerization therefore enables the in situ synchronized polymerization through continuous carbon-carbon bond formation and complete modification through carbon-azide bond formation simultaneously.

Synthesis of difluoromethylated allenes through trifunctionalization of 1,3-enynes.

Organofluorine compounds have shown their great value in many aspects. Moreover, allenes are also a class of important compounds. Fluorinated or fluoroalkylated allenes might provide an option as candidates for drug and material developments, as allenes allow a great number of valuable transformations.

Iron-catalyzed carboazidation of alkenes and alkynes.

Carboazidation of alkenes and alkynes holds the promise to construct valuable molecules directly from chemical feedstock therefore is significantly important. Although a few examples have been developed, there are still some unsolved problems and lack of universal methods for carboazidation of both alkenes and alkynes. Here we describe an iron-catalyzed rapid carboazidation of alkenes and alkynes, enabled by the oxidative radical relay precursor t-butyl perbenzoate.

Copper-Catalyzed Radical 1,4-Difunctionalization of 1,3-Enynes with Alkyl Diacyl Peroxides and N-Fluorobenzenesulfonimide.

Many reactions involving allenyl ion species have been studied, but reactions involving allenyl radicals are less well understood, perhaps because of the inconvenience associated with the generation of short-lived allenyl radicals. We describe here a versatile method for the generation of allenyl radicals and their previously unreported applications in the intermolecular 1,4-carbocyanation and 1,4-sulfimidocyanation of 1,3-enynes. With the assistance of the trifunctional reagents, alkyl diacyl peroxides or N-fluorobenzenesulfonimide, a range of synthetically challenging multisubstituted allenes can be prepared with high regioselectivity.

Impact of the Valence Charge of Transition Metals on the Cobalt- and Rhodium-Catalyzed Synthesis of Indenamines, Indenols, and Isoquinolinium Salts: A Catalytic Cycle Involving M/M [M = Co, Rh] for [4 + 2] Annulation.

Reaction mechanisms for the synthesis of indenamines, indenols, and isoquinolinium salts through cobalt- and rhodium-catalysis were investigated using density functional theory calculations. We found that the valence charge of transition metals dramatically influences the reaction pathways. Catalytic reactions involving lower-oxidation-state transition metals (M/M, M = Co and Rh) generally favor a [3 + 2] cyclization pathway, whereas those involving higher oxidation states (M/M) proceed through a [4 + 2] cyclization pathway.

Multicomponent reactions of phosphines, enynedioates and benzylidene malononitriles generated highly substituted cyclopentenes through an unexpected phosphine α-addition-δ-evolvement of an anion pathway.

Multicomponent reactions of phosphines, enynedioates and benzylidene malononitriles provide highly substituted syn-selective cyclopentenes appending the phosphorus ylide moiety in good yield with a diastereoselectivity of up to 100% through resonance-derived 1,5-dipolar species as the key intermediates, via the nucleophilic α(δ')-attack of phosphines toward enynedioates followed by addition to benzylidene malononitriles and 5-exo-dig cyclization. Through computational analyses, the overall reactions for the formation of syn- and anti-diastereomers are both exothermic with 65.6 and 66.

Effects of iodine on the relaxation dynamics of a photoexcited I(-)(H(2)O)(4) cluster.

The Born-Oppenheimer molecular dynamics are used to examine the relaxation dynamics of the charge-transfer-to-solvent (CTTS) photoexcited electron in I(-)(H2O)4. The dynamics are initiated from the C1' cluster configuration, which contains a dangling water molecule. The iodine atom is found to exert a repulsive force on the photoexcited electron at the beginning but an attractive force at later times of the simulation.

Exploring water binding motifs to an excess electron via X2(-)(H2O) [X = O, F].

X(2)(-)(H(2)O) [X = O, F] is utilized to explore water binding motifs to an excess electron via ab initio calculations at the MP4(SDQ)/aug-cc-pVDZ + diffs(2s2p,2s2p) level of theory. X(2)(-)(H(2)O) can be regarded as a water molecule that binds to an excess electron, the distribution of which is gauged by X(2). By varying the interatomic distance of X(2), r(X1-X2), the distribution of the excess electron is altered, and the water binding motifs to the excess electron is then examined.

Potential energy surface of O2-(H2O) and factors controlling water-to-O2- binding motifs.

The potential energy surface (PES) of O(2)(-)(H(2)O) is investigated by varying the interoxygen distance of O(2)(-) via ab initio calculations with a large basis set. Although two stationary points, C(s) and C(2v) conformers, are found along the interoxygen-distance coordinate, only the C(s) conformer is identified as a minimum-energy species. We find a critical distance, r(c), separating these two conformers in the PES.

Tuning through-bond Fe(III)/Fe(II) coupling by solvent manipulation of a central ruthenium redox couple.

The relationships between the intervalence energy (E(IT)) and the free energy difference (DeltaG) that exists between the minima of redox isomers (Fe(II)-Ru(III)/Fe(III)-Ru(II)) for various heterobimetallic complexes [(R-Fcpy)Ru(NH(3))(5)](2+/3+) (R = H, ethyl, Br, actyl; Fcpy = (4-pyridyl)ferrocenyl; Ru(NH(3))(5) = pentaam(m)ineruthenium) were examined. The changes in DeltaG for the complexes in various solvents were due to the effects of both solvent donicity and the substituents. The intervalence energy versus DeltaG, DeltaG approximately FDeltaE(1/2) (DeltaE(1/2) = E(1/2)(Fe(III/II)) - E(1/2)(Ru(III/II))), plots for the complexes in various solvents suggest a nuclear reorganization energy (lambda) of approximately 6000 cm(-1) (Chen et al.