Unified Photoredox-Catalyzed Aerobic Oxidative Dynamic Kinetic Asymmetric Transformation for C-N Atropoisomers Mediated by Chiral Organophosphites.

The synthesis of anilides with a chiral C(═O)-N axis has relied on direct installation of the chiral C(sp)-N(sp) bond or enantioselective modification of the peripheral groups. However, these methods are constrained by the size and type of functional groups compatible with each strategy. Herein, we report a dynamic kinetic asymmetric transformation (DYKAT) for the aerobic oxidation of iminium ions to access C(═O)-N axial chirality that addresses those limitations.

Synthesis, crystal structure and Hirshfeld surface analysis of bis-[2-amino-5-(ethyl-sulfan-yl)-1,3,4-thia-diazol-3-ium] bis-(perchlorato-κ)bis-(picolinato-κ ,)copper(II).

In the title coordination complex, (CHNS)[Cu(CHNO)(ClO)], the Cu center exhibits a distorted octa-hedral geometry with an equatorial plane formed by two bidentate picolinato ligands and axial coordination from two perchlorate anions, consistent with a Jahn-Teller distortion. The crystal structure is further consolidated by a network of hydrogen bonds involving the thia-diazole-based cations, which reside in the outer coordination sphere in a unique protonated state. Hirshfeld surface analysis reveals that O⋯H/H⋯O contacts dominate the inter-molecular inter-actions, contributing significantly to the crystal packing.

Synthesis, crystal structure and Hirshfeld surface analysis of 5-methyl-2-[(1,3-thia-zol-2-yl)sulfan-yl]-1,3,4-thia-diazole.

The title compound, CHNS, consists of two biologically relevant heterocyclic units, suggesting potential biological activity and possible use as a ligand in metal complexation. The compound crystallizes in the monoclinic space group 2/ and features non-classical inter-molecular C-H⋯N hydrogen bonds, along with π-π stacking inter-actions that contribute to the crystal cohesion. Hirshfeld surface analysis highlights significant inter-molecular inter-actions including, among others, N⋯H/H⋯N, S⋯H/H⋯S, and S⋯C/C⋯S contacts.

Magnesium-Catalyzed Primary, Secondary, and Tertiary Amide Hydroboration.

Catalytic hydroboration of amides is highly important because the resultant amines are commonly found in natural products, pharmaceuticals, agrochemicals, dyes, and other applications. In comparison to the conventional reduction of amides using (over)stoichiometric reductants, hydroboration of amides using magnesium compounds represents a green and sustainable approach because magnesium is both Earth abundant and environmentally benign. However, there is only one report on magnesium-catalyzed deoxygenative hydroboration of secondary and tertiary amides.

Correction: Uncovering diverse reactivity of NHCs with diazoalkane: C-H activation, C[double bond, length as m-dash]C bond formation, and access to N-heterocyclic methylenehydrazine.

[This corrects the article DOI: 10.1039/D4SC05740F.].

Desymmetrization of myo-inositol.

Chemistry and biology of phosphoinositols have been intensely investigated areas of research over the last 4-5 decades due to their involvement in cellular signal transduction pathways. Efficient laboratory synthesis of enantiomeric derivatives of inositols was a central issue since they were required for the delineation of the myo-inositol cycle as well as for the total synthesis of polyol based natural products and their derivatives. This essentially meant the development of competent methods for the desymmetrization of myo-inositol leading to the preparation of enantiomeric O-substituted derivatives of myo-inositol.

Catalyst and transition-metal free 1,6-conjugate addition of azobisisobutyronitrile: access to isobutyronitrile containing diarylmethanes.

A catalyst and transition-metal free 1,6-conjugate addition of azobisisobutyronitrile to -quinone methides for the synthesis of isobutyronitrile containing diarylmethanes has been achieved. This protocol enables the synthesis of isobutyronitrile containing diarylmethanes in good yields and with a broad substrate scope. This is the first example wherein azobisisobutyronitrile has been used as a cyanide source for 1,6-conjugate addition under catalyst and metal-free conditions.

Investigating the visible range photoresponse of an organic single-crystal analogue of the green fluorescent protein.

The growing demand for lightweight, flexible, semi-transparent and low-cost photodetectors (PDs) in wearable electronics and optical communication systems has prompted studies to investigate organic materials as feasible alternatives to conventional inorganic PDs. However, modern organic PDs often face responsivity, detectivity, and photoresponse speed limitations, particularly in the visible range. Here, we present the photoresponse of an organic single-crystal analogue of the green fluorescent protein (GFP) chromophore photodetector, fabricated on a silicon nitride substrate.

Regioisomeric π-Extended Nanographene with Long-Lived Phosphorescence Afterglow.

The cutouts of graphene sheets, particularly those with a nonplanar topology, present vast opportunities for advancement. Even a slight deviation from the planar structure can lead to intriguing (chiro)optical features for helically twisted nanographenes. In this context, we introduce two regioisomeric π-extended nanographenes that exhibit distinct excited-state characteristics.

Synthesis of Imine-Phenoxy Ligated Palladium Complexes for Norbornene Homopolymerization.

Metal complexes with tunable ligands play a crucial role in olefin polymerization and impart control over molecular weight, crystallinity, and stereoregularity. We report the single-step synthesis of imine-phenoxy ligands in excellent yields (81-93%). The identity of electronically tuned imine-phenoxy ligands was unambiguously ascertained by using a combination of spectroscopic and analytical methods.

Studies on the Stereoselective Synthesis of Sacubitril via a Chiral Amine Transfer Approach.

We present a comprehensive account of our efforts directed towards the synthesis of sacubitril, a neprilysin inhibitor used in combination with valsartan and marketed as Entresto™. Our initial approach to the formal synthesis of sacubitril employed a chiral pool strategy, utilizing (S)-pyroglutamic acid as a key building block and Cu(I)-mediated Csp-Csp cross-coupling as a key transformation. Further investigations led to the development of chiral amine transfer (CAT) reagents-based stereoselective synthesis.

Regio- and Stereoselective Construction of 1,3,5-Triaroylcyclohexanes via KOBu-Mediated Cyclotrimerization of Aryl Vinyl Ketones.

Herein, we disclose a simple one-pot method for an efficient regio- and stereoselective synthesis of 1,3,5-triaroylcyclohexanes from aryl vinyl ketones using potassium -butoxide. The developed protocol allows the construction of various symmetrically substituted cyclohexanes in good to excellent yields. The major product also can be converted to the product (all equatorial) conveniently by acid catalysis.

Catalytic Cycloisomerization-Oxidative Cyclization Reaction Sequence of Enyne Diesters Derived from 2-Propargyloxyarylaldehydes.

Enyne diesters derived from 2-propargyloxyarylaldehydes are converted into 2-oxopyranochromenes via In(OTf)-catalyzed cycloisomerization and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)-mediated oxidative cyclization reaction sequence in one pot. The process possesses broad substrate scope and good functional group compatibility and generates various 4-(hetero)aryl-substituted 2-oxopyranochromenes in 32-79% yields (over two steps). 2-Oxopyranochromenes undergo selective decarboxylation under Krapcho conditions.

Chelation-assisted and steric-controlled selectivity in the Pd-catalyzed C-H/C-H oxidative coupling of indoles.

We report the first regioselective C2-C7 oxidative coupling of indoles using a palladium catalyst upon the strategic installation of -pyridinyl and C3-carbonyl, which delivers 2,7-biindoles with a broad scope (25 examples; up to 93% yield). Isolation of the catalytic intermediate reveals the initial activation of the C(7)-H bond, followed by the C(2)-H bond in indoles, and the reaction proceeds a Pd(II)/Pd(0) pathway.

Uncovering diverse reactivity of NHCs with diazoalkane: C-H activation, C[double bond, length as m-dash]C bond formation, and access to N-heterocyclic methylenehydrazine.

N-heterocyclic carbenes (NHCs) have attracted significant attention due to their strong σ-donating capabilities, as well as their transition-metal-like reactivity towards small molecules. However, their interaction with diazoalkanes remains understudied. In this manuscript, we explore the reactivity of a series of stable carbenes, encompassing a wide range of electronic properties, with MeSiCHN.

1,6-Conjugate addition of generated aryldiazenes to -quinone methides.

Herein we report a transition-metal free, base-mediated 1,6-conjugate addition of aryldiazenes to -quinone methides (-QMs). Arylhydrazines were used for the generation of aryldiazenes using a base-mediated protocol in the presence of air as the oxidant. The 1,6-conjugate addition of aryldiazenes to -quinone methides a radical mechanism is followed by an oxidative rearrangement to furnish the desired product, arylhydrazones.

Thermally Stable P-Chiral Supramolecular Phosphines, their Self-Assembly and Implication in Rh-Catalyzed Asymmetric Hydrogenation.

P-chiral supramolecular phosphine ligands are crucial for asymmetric transformations, but their synthesis is tedious. We report a one-step synthesis of thermally stable P-chiral supramolecular phosphines and their performance in the asymmetric hydrogenation of functionalized alkenes. A rational designing and synthesis of (R, R)-QuinoxP* ligated palladium complex (Pd-2) in excellent yield is reported.

Boron- and Oxygen-Doped π-Extended Helical Nanographene with Circularly Polarised Thermally Activated Delayed Fluorescence.

Helical nanographenes have garnered substantial attention owing to their finely adjustable optical and semiconducting properties. The strategic integration of both helicity and heteroatoms into the nanographene structure, facilitated by a boron-oxygen-based multiple resonance (MR) thermally activated delayed fluorescence (TADF), elevates its photophysical and chiroptical features. This signifies the introduction of an elegant category of helical nanographene that combines optical (TADF) and chiroptical (CPL) features.

A solid-state NMR method for characterization of pharmaceutical eutectics.

Pharmaceutical eutectics are extremely useful for designing formulations, and currently, there are no techniques other than differential scanning calorimetry (DSC) that can confirm their formation. In this study, we demonstrate that H fast magic angle spinning (MAS) solid-state NMR (SSNMR) experiments can confirm the formation of eutectics by detecting their intermolecular hydrogen bonding interactions.

Intramolecular donor-stabilized tetra-coordinated germanium(iv) di-cations and their Lewis acidic properties.

We report the first examples of intramolecular phosphine-stabilized tetra-coordinated germanium(iv) di-cationic compounds: [LGe][CFSO]3 and [LGe][CFSO]3 (L = 6-(diisopropylphosphanyl)-1,2-dihydroacenaphthylene-5-ide; L = 6-(diphenylphosphanyl)-1,2-dihydroacenaphthylene-5-ide). The step wise synthetic strategy involves the isolation of neutral and mono-cationic Ge(iv) precursors: [LGeCl][X] (X = GeCl1, OTf 2), [LGeCl] 1 and [LGeCl][OTf] 2. Both 3 and 3 exhibit constrained spiro-geometry.

Tridentate NacNac Tames T-Shaped Nickel(I) Radical.

The reaction of a nickel(II) chloride complex containing a tridentate β-diketiminato ligand with a picolyl group [2,6-iPr -C H NC(Me)CHC(Me)NH(CH py)]Ni(II)Cl (1)] with KSi(SiMe ) conveniently afforded a nickel(I) radical with a T-shaped geometry (2). The compound's metalloradical nature was confirmed through electron paramagnetic resonance (EPR) studies and its reaction with TEMPO, resulting in the formation of a highly unusual three-membered nickeloxaziridine complex (3). When reacted with disulfide and diselenide, the S-S and Se-Se bonds were cleaved, and a coupled product was formed through carbon atom of the pyridine-imine group.

NHC-Catalyzed Enantioselective Synthesis of Tetracyclic δ-Lactones by (4 + 2) Annulation of -Quinodimethanes with Activated Ketones.

The N-heterocyclic carbene (NHC)-catalyzed generation of -quinodimethanes (-QDMs) from 9-fluorene-1-carbaldehydes followed by the interception with activated ketones resulting in the enantioselective synthesis of tetracyclic δ-lactones is presented. High diastereoselectivity of products, remote C(sp)-H functionalization, broad substrate scope, and mild reaction conditions are the notable features of the present (4 + 2) annulation.

Synthesis of novel rhodamine type Anthrone Spiro-lactam (ASL) analogues and evaluation of antiviral activity against dengue and chikungunya viruses.

A series of Rhodamine type Anthrone-Spirolactam (ASL) derivatives Benzylimin-Anthrone-Spirolactam (ASL-1 to ASL-10) and Benzamide-Anthrone-Spirolactam (ASL-11 and ASL-12) were synthesized via a simple condensation reaction between Anthrone Spiro-lactamine (2) and various aromatic aldehyde and acyl chlorides respectively. Since rhodamine-based compounds were reported to have antiviral activity, the ASL derivatives were examined for in vitro antiviral activity against dengue and chikungunya viruses. Among all the analogues, ASL-3, ASL-6, ASL-7, ASL-8, ASL-9 and ASL-10 were the most potent against dengue virus (DENV) and exerted around one log reduction in virus titre under post-treatment conditions.

Isomer Effect on Energy Storage of π-Extended S-Shaped Double[6]Heterohelicene.

Recently, chiral and nonplanar cutouts of graphene have been the favorites due to their unique optical, electronic, and redox properties and high solubility compared with their planar counterparts. Despite the remarkable progress in helicenes, π-extended heterohelicenes have not been widely explored. As an anode in a lithium-ion battery, the racemic mixture of π-extended double heterohelical nanographene containing thienothiophene core exhibited a high lithium storage capability, attaining a specific capacity of 424 mAh g at 0.

Crystal structure of 1-(4-bromo-phen-yl)but-3-yn-1-one.

The title compound, 1-(4-bromo-phen-yl)but-3-yn-1-one, CHBrO, crystallizes in the monoclinic space group 2/ with one mol-ecule in the asymmetric unit. The structure displays a planar geometry. The crystal structure is consolidated by C-H⋯O hydrogen bonding and a short C=O⋯C≡C (acetyl-ene) contacts.