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A protocol has been developed for the synthesis of six‐ and seven‐membered ring lactams fused to coumarins through a hydroaminocarbonylation reaction catalyzed by palladium. The catalytic system (PdBr2/Xantphos) provided a strategy for the synthesis of seven‐membered ring lactams with good isolated yield and regioselectivity. Control of selectivity by the substrate in the synthesis of six‐membered ring lactams was observed. Control reactions showed the importance of the hydrogen in the cyclocarbonylation reaction, and NMR data supported the role of the hydride palladium species as a catalytic precursor. A preliminary screening of the cytotoxic activity of coumarin‐fused lactams against six cancer cell lines was evaluated. The biological tests indicated that both the size of the heterocycle and presence of a substituent on the aromatic ring affected the inhibition of cell growth. [ABSTRACT FROM AUTHOR]

A series of pyridylimine ligands with variations of the substituent at the imine nitrogen were synthesized and coordinated to the [MoCl2O2] core. The novel molecular structures of the complexes were fully characterized by 1H and 13C NMR, FT‐IR, ESI, EA, and X‐ray crystallography, and their catalytic activity was studied for the epoxidation of alkenes using tert‐butyl hydroperoxide (TBHP) as the oxidant. The new complexes showed excellent catalytic activity and fine selectivity in the epoxidation reaction compared with similar homogeneous molybdenum complexes. The results demonstrated that there is a significant change in the catalytic performance, depending on the alkyl arm on the structure of the pyridilimine ligand. The catalytic results indicated that complex [MoCl2O2(L)] (L: N‐(2‐Pyridinylmethylene)‐1‐tert‐butylimine) C5 is the best catalytic precursor in the epoxidation of cyclohexene (TON: 92920 and TOF: 30974 h−1). [ABSTRACT FROM AUTHOR]

Seven‐membered ring lactones fused to coumarin scaffolds were obtained via a palladium‐catalyzed regioselective intramolecular alkoxycarbonylation under a CO atmosphere. Cyclocarbonylation of 3‐allyl‐4‐hydroxycoumarin derivatives was accessed in the absence of hydrogen gas, acidic conditions, or any other additives. The results of the control experiments revealed the importance of pKa of the substrate for initiating the reaction. [ABSTRACT FROM AUTHOR]

A versatile route has been developed for the synthesis of 2‐arylindoles using a Pd‐catalyzed tandem process. Under reductive conditions, different 2‐arylindoles were synthesized from phenylglyoxal and aniline. This synthetic methodology involves a tandem reaction of four steps with high regioselectivity. Alternatively, 2‐anilinoacetophenones intermediates also can be using to give access to the corresponding 2‐arylindoles. [ABSTRACT FROM AUTHOR]

In their Research Article, K. Almaraz and M. Amézquita-Valencia prepared a new series of six- and seven-membered ring lactam fused to coumarin core via Pd-catalyzed hydroaminocarbonylation reaction under syngas conditions. Keywords: Cyclocarbonylation; Lactam; Palladium; Regioselectivity; Medium-sized heterocycles EN Cyclocarbonylation Lactam Palladium Regioselectivity Medium-sized heterocycles 1 1 1 08/23/23 20230821 NES 230821 B The Cover Feature b , designed by Hortensia Segura, illustrates a brave little cat (the catalyst) jumping onto a garden wall, crossing a seven-membered ring lactam fused to a coumarin scaffold. Cover Feature: Pd-Catalyzed Intramolecular Hydroaminocarbonylation of 3-Allyl-4-arylaminocoumarins: Synthesis of Six- and Seven-membered Ring Lactams Fused to the Coumarin Scaffold (ChemCatChem 16/2023). [Extracted from the article]

Herein, we report a new straightforward catalytic synthesis of 2,3-disubstituted indoles from α-diketones 1 and N-substituted anilines 2 by employing a palladium(II) trifluoroacetate/1,1′-bis(diphenylphosphino)ferrocene ([Pd(tfa)2]/dppf; 1:1.5) under reductive conditions and without an external oxidant. The tandem reaction involves ketoenamine and ketoamine as intermediates and a final dehydration-annulation reaction to obtain the 2,3-disubstituted indole. New palladium hydride species, which catalyze the reaction, could not be isolated but Pd-H species were observed by NMR and IR spectroscopy and mass spectrometry (FAB+) studies. This work presents a new regioselective route with a plausible mechanism to synthesize 2,3-disubstituted indoles under reductive conditions. [ABSTRACT FROM AUTHOR]

An unprecedented C-benzylation rearrangement reaction, catalyzed by palladium, is reported. The reaction proceeds by rearrangement leading to the direct synthesis of para or ortho benzyl-substituted N-methylanilines. The product is obtained in high regioselectivity, without the need to use a ligand for the catalytic process. [ABSTRACT FROM AUTHOR]

A simple and regioselective synthesis of phenoxy esters and phenylthio esters is reported. The products are obtained by selective alkoxycarbonylation catalyzed by Pd2(dba)3, 1,4-bis(diphenylphisphino)butane (dppb), and syngas (CO/H2) in chloroform/alcohol. This methodology affords bifunctional products in good yield with excellent n-selectivity and without the need to use additives. [ABSTRACT FROM AUTHOR]

The phosphine ligand mediated palladium catalyzed alkoxycarbonylation of alkenes was investigated with the objective of attaining good linear selectivity for the ester. The effect of various parameters such as solvents, additives, palladium precursors, CO pressures, and alkenes of various structural complexities were examined. The results revealed the importance of using a Lewis acid such as SnCl2 or Ti(OiPr)4 in combination with a monodentate ligand such CYTOP 292 or P(p-anisyl)3 to enhance the regioselectivity for the linear isomers in the range of 70-96%. [ABSTRACT FROM AUTHOR]

We report the synthesis of new prochiral imines by the reaction of nonsymmetric benzophenone derivates, bencylamines, and anilines in good yields. All the products were characterized by1H and13C NMR as an isomericE/Zmixture. Also, the molecular structures for five derivatives determined by single-crystal x-ray experiments are presented. Supplemental materials are available for this article. Go to the publisher's online edition ofSynthetic Communications® to view the free supplemental file. [ABSTRACT FROM AUTHOR]

Abstract: The first example of asymmetric hydrogenation of imines using Co2(CO)8/(R)-BINAP/H2/CO system was developed. The reaction conditions were screened with a wide range of N-aryl benzophenone ketimines, obtaining products with excellent yields and good enantiomeric excess. Moreover, a pathway is suggested based on the isolation and characterization of several catalyst intermediates. [Copyright &y& Elsevier]

Abstract: A direct PdBr2(BINAP)-complex catalyzed method has been developed to produce 2,3-disubstituted indoles by the reaction of arylamines with α-diketones under reductive (H2) conditions. The synthetic methodology involves a tandem reaction of three steps and all the organic intermediates were isolated and characterized, the reduction products in this sequence are chiral and present interesting enantiomeric excess. This report constitutes a new and different route to synthesize indoles and a plausible mechanism is also suggested. [Copyright &y& Elsevier]

The phosphine ligand mediated palladium catalyzed alkoxycarbonylation of alkenes was investigated with the objective of attaining good linear selectivity for the ester. The effect of various parameters such as solvents, additives, palladium precursors, CO pressures, and alkenes of various structural complexities were examined. The results revealed the importance of using a Lewis acid such as SnCl2 or Ti(O(i)Pr)4 in combination with a monodentate ligand such CYTOP 292 or P(p-anisyl)3 to enhance the regioselectivity for the linear isomers in the range of 70-96%.

A simple, efficient, and regioselective synthesis of 3-methyl-3,4-dihydrocoumarins is reported. The reaction of 2-allyl phenols with synthesis gas was catalyzed by PdI2, and 1,3,5,7-tetramethyl-6-phenyl-2,4,8-trioxa-6-phosphaadamantane (L1) and 1,3,5,7-tetramethyl-6-tetradecyl-2,4,8-trioxa-6-phosphaadamantane (L2) were effective as ligands, affording good product selectivity in all cases.

The title compound, C(18)H(27)NO(2), crystallizes as the enamine form with Z geometry. The β-enamino-ester fragment forms a dihedral angle of 87.5 (1)° with the isopropyl-phenyl frame. The structure exhibits an intra-molecular N-H⋯O hydrogen bond. In addition, in the crystal, mol-ecules are linked by a centrosymmetric inter-molecular N-H⋯O hydrogen bond.

The title compound, C(15)H(21)NO(2), was obtained by the reaction of acetoacetate with 2,4,6-trimethyl-aniline using Mexican bentonitic clay as a catalyst. It crystallizes in the enamine form. The β-enamino ester residue is almost perpendicular to the aromatic ring [dihedral angle = 88.10 (6)°]. The mol-ecular conformation is stabilized by a strong intra-molecular N-H⋯O hydrogen bond. In addition, the N-H group forms a weak inter-molecular N-H⋯O hydrogen bond linking the mol-ecules into centrosymmetric dimers.