Nanoparticles derived from FeCl3 containing the ligand XPhos and only 500 ppm Pd effect Sonogashira couplings in water between rt and 45 °C. The entire aqueous reaction medium can be easily recycled using an “in-flask” extraction. Several tandem processes in one pot are illustrated, including a sequence involving five steps (10 reactions) in good overall yield.

on the occasion of his 67th birthday Highly selective directm onofluorinationo fi ndolesa nd arenes was developed through an approacht hat allows site-specific solubility of substrate and fluorine source in the micelle. This approachw as highly selectivef or ab road range of substrates with excellent functional group tolerance. Differences in binding constant and solubility of indoles and arenes in the micelle allowed the fine-tuning of selectivity.C ontrol experiments suggested ar adicalp athway and provided insighti nto the role of micelles of the environmentally benigna mphiphile PS-750-M. Dynamicl ight scattering experiments stronglyi ndicated the site-specific solubility of the substrate and fluorine source.T he methodology was successfully adapted to gram scale, and the E-factore stablished from ar ecycle study indicated that the process is environmentally responsible and sustainable.

Both Ni(0) complexes and nanoparticles (NPs) are unstable in water, which poses a significant hindrance to their application in aqueous synthetic catalysis. To overcome these barriers, ligated Ni(0) nanoparticles (diameter <1 nm) containing a minimum amount of Pd(0) in the microballs formed of amphiphile PS-750-M are developed and applied in the highly selective carbamate cleavage. Selectivity and functional group tolerance are thoroughly investigated. Control experiments revealed the importance of an individual component of the nanocatalyst. Use of our proline-based amphiphile PS-750-M is critical for achieving microball architecture, the stability of nanoparticles, and desired catalytic activity. Once formed, microballs can be isolated and stored at ambient temperature. Catalyst is thoroughly characterized by Xray photoelectron spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy, thermogravimetric analysis, infrared, and cyclic voltammetry. For selective catalysis, zero oxidation state of both Ni and Pd is crucial. On the basis of catalyst characterization and control experiments, the plausible reaction mechanism is proposed.

A scalable synthetic method is described for both the preparation of ultrasmall palladium nanoparticles and their subsequent use in catalyzing an αarylation reaction of nitriles in aqueous micelles. This method involves the intermediacy of carbanions or keteniminates, which are presumably stabilized by the micellar environment rather than being quenched with water. These Pd nanoparticles are thoroughly characterized. Mechanistic studies using 31 P NMR spectroscopy revealed the binding of phosphine ligand with the Pd surface and control experiment confirmed the zero-oxidation state of palladium. The scope of the transformation is demonstrated over 35 examples, including one at 50 g scale.

Amberlyst A21 was found to be an extremely efficient catalyst for synthesis of a series of 6-amino-4-alkyl/ aryl-3-methyl-2,4-dihydropyrano[2,3-c]pyrazole-carbonitriles by a four-component reaction of a mixture of ethyl acetoacetate, hydrazine hydrate, aldehyde, and malononitrile in ethanol at room temperature. The catalytic efficiency of Amberlyst A21 was compared with some other resin-bound free and anionic bases in order to ascertain the best catalyst for the said conversion. The catalyst was found to work extremely well also for acyclic/cyclic ketones to give corresponding dihydropyrano[2,3-c]pyrazoles or their spirocyclic variants. Easy recovery of the catalyst and its reusability, room temperature reaction conditions, short reaction time, excellent yields, no chromatographic purification, and evasion of environmentally hazardous solvents in the entire reaction process may make this protocol very useful for academia and industry.