Vutukuri Prakash Reddy

Nano Indium Oxide as a Recyclable Catalyst for C−S Cross-Coupling of Thiols with Aryl Halides under Ligand Free conditions

An efficient ligand-free C-S cross-coupling of aryl halides with aromatic/alkyl thiols has been developed using a catalytic amount of nanocrystalline indium oxide as a recyclable catalyst with KOH as the base in DMSO at 135 degrees C. A variety of aryl sulfides can be synthesized in excellent yields utilizing this protocol.

Copper Oxide Nanoparticle-Catalyzed Coupling of Diaryl Diselenide with Aryl Halides under Ligand-Free Conditions

A new, efficient and ligand-free cross-coupling reaction of aryl halides and diaryl diselenides using a catalytic amount of nanocrystalline CuO as a recyclable catalyst with KOH as the base in DMSO at 110 degrees C is reported. This protocol has been utilized for the synthesis of a variety of aryl selenides in excellent yields from the readily available aryl halides and diaryl diselenides.

Rhodium-catalyzed intermolecular oxidative cross-coupling of (hetero)arenes with chalcogenophenes.

A straightforward and efficient method for the rhodium-catalyzed intermolecular oxidative cross-coupling of arenes and heteroarenes with thio- and selenophene derivatives (chalcogenophenes) via double C-H bond cleavage has been developed by using Cu(OAc)2/AgSbF6 as an oxidant. The reaction is applicable to a wide range of (hetero)arenes carrying a directing group and chalcogenophenes to yield substituted biaryl heterocyclic derivatives and oligothiophene derivatives in moderate to high yields.

The Palladium-Catalyzed Intermolecular C–H Chalcogenation of Arenes

Palladium catalyzes the intermolecular chalcogenation of carbazole, 2-phenylpyridine, benzo[h]quinolone, and indole derivatives with disulfides and diselenides via selective C-H bond cleavage, providing a convenient route to thio and selenoethers.

Copper-mediated thiolation of carbazole derivatives and related N-heterocycle compounds

The copper-mediated direct thiolation of carbazole derivatives with disulfides via C(sp2)–H bond cleavage was developed for synthesizing diaryl and alkyl aryl sulfides. This reaction exhibits wide tolerance toward various functional groups giving the products in good yields without any additives or ligands, and can be easily extended to the synthesis of thioethers carrying a benzo[h]quinolone, 2-phenylquinoline, or indole moiety in satisfactory yields.

NickelButadiene Catalytic System for the Cross-Coupling of Bromoalkanoic Acids with Alkyl Grignard Reagents: A Practical and Versatile Method for Preparing Fatty Acids

Fatty acids are essential to natural life because they act as key components in biological membranes and glycerides, as well as in various biologically active agents, such as prostaglandins and endocannabinoids. For the construction of structurally diverse carbon frameworks of fatty acids, transition-metal-catalyzed cross-coupling reactions appear to be the most straightforward and efficient methods for carbon carbon bond formation and they have been employed in the synthesis of a wide variety of fatty acids with unsaturated bonds. However, these methods are limited to reactions at sp or sp carbon atoms, in which the stereochemistry of the olefinic moieties that are being introduced must be controlled. In contrast to these reactions, cross-coupling reactions between sp-hybridized carbon centers appear to be a useful and, potentially, more-promising tool, because they are applicable to the synthesis of both saturated and unsaturated fatty acids and they are free from the problems associated with double-bond stereochemistry. However, owing to the lower tolerance of the carboxylic group toward organometallic reagents, including transition-metal complexes, protected carboxy groups or their synthetic equivalents are often employed. Herein, we report a convenient and efficient one-pot procedure for the construction of carbon frameworks of fatty acids by using the nickelcatalyzed cross-coupling of alkyl halides that contain a carboxy functionality with Grignard reagents in the presence of 1,3-butadiene as an additive, in combination with an in situ protection procedure. As an example of a synthetic application of this method, the regioisomers of elaidic acid were synthesized through an iterative cross-coupling procedure. In our previous studies, we reported that the Ni-catalyzed cross-coupling reactions of alkyl halides with alkyl Grignard reagents in the presence of butadienes were effective for the construction of hydrocarbon skeletons that contained aprotic polar functionalities, such as ketones, esters, and nitriles. When alkyl halides that contained a carboxylic acid group are subjected to this cross-coupling reaction, without employing tedious protection-deprotection processes, the deprotonation of the carboxylic acid group is unavoidable. Thus, to develop a simple and straightforward route to fatty acids with various carbon chains, we examined the Ni-catalyzed cross-coupling reactions of 6-bromohexanoic acid (1a) with excess amounts of nBuMgCl under various conditions and we found that the expected decanoic acid was obtained in quantitative yield as the sole product, with no evidence of any undesirable side reactions, when the reaction was conducted at 0 8C for 1 h in the presence of 2.4 equivalents of nBuMgCl (Scheme 1). In this reaction, a