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.

On the competition between six-membered and five-membered NHC towards alane centered ring expansion.

The combination of 6-SIDipp·AlH (1) and 5-IDipp resulted in the ring expansion of 6-NHC, while the five-membered NHC remained unchanged, which was subsequently explained by DFT studies. Besides, the substitution chemistry of 1 was also studied with TMSOTf and I, which gave rise to the substitution of a hydride by triflate or iodide ligands.

Iron-Catalyzed Alkoxylation, Dehydrogenative-Polymerization and Tandem Hydrosilylative-Alkoxylation.

Alkoxylation, hydrosilylative-alkoxylation, and dehydrogenative-polymerization are some of the most widely used transformations in synthetic chemistry. However, these transformations are traditionally catalyzed by precious, and rare late-transition metals. Presented here is a molecularly defined iron complex that catalyzes alkoxylation, tandem hydrosilylative-alkoxylation, and dehydrogenative polymerization of silanes under mild conditions.

Manganese(I)-Catalyzed Chemoselective Transfer Hydrogenation of the C=C Bond in Conjugated Ketones at Room Temperature.

Chemoselective transfer hydrogenation of C=C bond in α,β-unsaturated ketones is demonstrated at room temperature employing a manganese(I) catalyst and half an equivalent of ammonia-borane (H N-BH ). A series of mixed-donor pincer-ligated Mn(II) complexes, ( PN N )MnX [κ ,κ ,κ -(N-(di-tert-butylphosphaneyl)-6-(1H-pyrazol-1-yl)pyridin-2-amine)MnX ] {X=Cl (Mn2), X=Br (Mn3), X=I (Mn4)} were synthesized and characterized. Amongst the Mn(II) complexes, (Mn2, Mn3, Mn4) and Mn(I) complex, ( PN N )Mn(CO) Br (Mn1) screened; the Mn1 acts as an efficient catalyst for the chemoselective C=C bond reduction in α,β-unsaturated ketones.

Organocatalysed one-pot three component synthesis of 3,3'-disubstituted oxindoles featuring an all-carbon quaternary center and spiro[2-pyran-3,4'-indoline].

A simple and efficient methodology for the one-pot synthesis of 3,3'-disubstituted oxindoles featuring an all-carbon quaternary center has been demonstrated through l-proline catalysed three-component reaction based on sequential Knoevenagel condensation/Michael addition and also one-pot synthesis of spiro[2-pyran-3,4'-indoline] through consecutive Knoevenagel condensation/Michael addition/reduction/cyclization reactions from readily available isatin derivatives, malononitrile, and ketones. The present methodology presents several advantages, including simple reaction set-up, short reaction times, and easy to work-up. Also, this strategy offers broad substrate scope with excellent yields and high atom economy, under mild reaction conditions.

Palladium-Catalyzed Chemoselective Oxygenation of C(sp)-H and C(sp)-H Bonds in Isatins.

The palladium-catalyzed chemoselective C(sp)-H and C(sp)-H bond oxygenation of substituted isatin derivatives is reported. This mild protocol exhibits the C5 C(sp)-H oxygenation of isatins through electrophilic intermolecular C-H palladation in concentrated solutions using PhI(OAc) or Selectfluor as an oxidant, whereas it exhibits-N-CH C(sp)-H oxygenation in dilute solutions via carbonyl-assisted intramolecular palladation in the presence of KSO. This oxygenation reaction provides a direct and unified approach for synthesizing diverse oxygenated isatins with sensitive functionalities, including biorelevant compounds.

An accelerated Rauhut-Currier dimerization enabled the synthesis of (±)-incarvilleatone and anticancer studies.

The total synthesis of racemic incarvilleatone has been achieved by utilizing unexplored accelerated Rauhut-Currier (RC) dimerization. The other key steps of the synthesis are oxa-Michael and aldol reactions in a tandem sequence. Racemic incarvilleatone was separated by chiral HPLC and the configuration of each enantiomer was determined by single-crystal X-ray analysis.

A zwitterionic disilanylium from an unsymmetrical disilene.

The reaction of PhC(NBu)SiSi(SiMe) (1) with MeSiCHCl afforded an unsymmetrical sp-sp disilene, 2, with concomitant elimination of MeSiCl. The analogous reaction with PhC(NBu)SiCl resulted in the oxidative addition of the C-Cl bond at the Si(II) atom (3). The reactions of 2 with sulfur and selenium led to compounds with SiE (ES (4) and Se (5)) double bonds.

Room temperature chemoselective hydrogenation of C[double bond, length as m-dash]C, C[double bond, length as m-dash]O and C[double bond, length as m-dash]N bonds by using a well-defined mixed donor Mn(i) pincer catalyst.

Chemoselective hydrogenation of C[double bond, length as m-dash]C, C[double bond, length as m-dash]O and C[double bond, length as m-dash]N bonds in α,β-unsaturated ketones, aldehydes and imines is accomplished at room temperature (27 °C) using a well-defined Mn(i) catalyst and 5.0 bar H. Amongst the three mixed-donor Mn(i) complexes developed, κ-(PNN)Mn(CO)Br (R = Ph, Pr, Bu); the Bu-substituted complex ( PNN)Mn(CO)Br shows exceptional chemoselective catalytic reduction of unsaturated bonds.