Synthesis of Aminobenzoic Acid Derivatives via Chemoselective Carbene Insertion into the −NH Bond Catalyzed by Cu(I) Complex

Phosphine ligand stabilized air-stable Cu­(I) complexes have been successfully used to functionalize the aromatic aminobenzoic acids in a chemoselective manner without implementing protection and deprotection strategy under mild reaction conditions. This chemoselective carbene insertion into −NH bond over −COOH and −OH bonds leads to the wide range of carboxy and hydroxy functionalized α-amino esters (27 examples). All of the isolated new products have been fully characterized using standard analytical methods

Synthesis of β‑Lactams through Carbonylation of Diazo Compounds Followed by the [2 + 2] Cycloaddition Reaction

Reporting an efficient method for the synthesis of β-lactams by the carbonylation of diazo compounds, using [Co2(CO)8] to corresponding ketenes, followed by [2 + 2] cycloaddition with imines. The newly developed strategy was successfully applied to electronically and structurally diverse substrates to produce the corresponding β-lactams under mild reaction conditions. Fourier transform infrared spectroscopy was employed to monitor ketene formation and the transformation of ketene into β-lactam. All the products were fully characterized by using various analytical and spectroscopic techniques

Chemoselective Carbene insertion into the N–H Bond over O–H Bond Using a Well-Defined Single Site (P–P)Cu(I) Catalyst

Phosphine-coordinated air-stable Cu­(I) catalyst (<b>1</b>) has been synthesized and characterized. Catalyst <b>1</b> is found to be active toward highly chemoselective carbene insertion into the N–H bond over the O–H bond and also over the formation of olefins when numerous aminophenols were treated with a variety of α-aryl diazoesters under normal experimental conditions

Chemoselective Carbene insertion into the N–H Bond over O–H Bond Using a Well-Defined Single Site (P–P)Cu(I) Catalyst

Phosphine-coordinated air-stable Cu­(I) catalyst (<b>1</b>) has been synthesized and characterized. Catalyst <b>1</b> is found to be active toward highly chemoselective carbene insertion into the N–H bond over the O–H bond and also over the formation of olefins when numerous aminophenols were treated with a variety of α-aryl diazoesters under normal experimental conditions

A Green Approach to the Synthesis of α‑Amino Phosphonate in Water Medium: Carbene Insertion into the N–H Bond by Cu(I) Catalyst

Synthesis of amino phosphonates is more important owing to their significant applications in the biological systems. There are few methods already known in the literature to make these molecules; however, known methods have their own disadvantages. In this regard, synthesis of different kinds of amino phosphonates have been achieved via phosphonate substituted carbene insertion into the N–H bond of aniline catalyzed by readily available copper salt under mild reaction conditions in water. In order to find an efficient catalyst for carbene insertion reaction in neat water, a large number of transition metal catalysts were screened, and we found that the [Cu­(CH₃CN)₄]­ClO₄ was the best catalyst under employed reaction conditions. Using this environmentally benign methodology (copper catalyzed reaction in water), a large number of biologically important amino phosphonates have been synthesized, isolated (37 examples), and characterized using standard analytical and spectroscopic techniques

Is copper(I) hard or soft? A density functional study of mixed ligand complexes

Fully optimized structures of three- and four-coordinated Ni (0), Cu(I) and Zn(II) complexes with varied combination of hard $(H_2O \hspace{2mm} or H_3N)$ and soft $(H_2S, H_3P)$ ligands were computed using density functional theory (DFT). Frequency calculations were carried out to ascertain that the structures were true minima. In the case of Cu(I) and Zn(II), the heat of formation (HOF) values are smaller with larger number of soft ligands. The increase in the HOF on replacing a soft ligand with a hard ligand is less for Cu(I) than for Zn(II). The corresponding HOF is negative for Ni(0) which is not stable with a complement of four hard ligands. The calculated chemical hardness parameters based on vertical ionization potentials clearly indicate the preference of four hard ligands for Zn(II) and four soft ligands for Ni(0). Significantly, the maximum chemical hardness was computed for Cu(I) complex $[Cu(PH_3)_3(NH_3)]^+$, a combination of three soft and one hard ligand. The conclusions derived from absolute hardness data computed for the complexes closely parallel the experimentally observed stability of Cu(I) with an optimum number of hard and soft ligands in its coordination sphere in solution

Colorimetric Sensing of Fluoride Ion by New Expanded Calix[4]pyrrole through Anion−π Interaction

Three new expanded calix[4]pyrroles were synthesized, where the two dialkylldipyrromethane units are linked via C–C double bonds. One of them, calix[2]bispyrrolylethene, colorimetrically senses fluoride ion only, owing to anion−<b>π</b> interaction in polar aprotic solvents

Colorimetric Sensing of Fluoride Ion by New Expanded Calix[4]pyrrole through Anion−π Interaction

Three new expanded calix[4]pyrroles were synthesized, where the two dialkylldipyrromethane units are linked via C–C double bonds. One of them, calix[2]bispyrrolylethene, colorimetrically senses fluoride ion only, owing to anion−<b>π</b> interaction in polar aprotic solvents