Prashant Gautam - Academia.edu (original) (raw)
Papers by Prashant Gautam
ACS Omega, 2019
This work documents the first palladium pincer complex-catalyzed carbonylative Sonogashira (CS) a... more This work documents the first palladium pincer complex-catalyzed carbonylative Sonogashira (CS) and carbonylative Suzuki−Miyaura (CSM) cross-coupling. Compared to previous protocols, which employ hazardous and toxic solvents, the aminophosphine pincer complex {[C 6 H 3-2,6-(NHP{piperidinyl} 2) 2 ]Pd(Cl)} (III) catalyzes both the cross-coupling reactions in propylene carbonate, an ecofriendly and sustainable polar aprotic solvent. Advantageously, employing III allows the CS cross-coupling to be carried out at a palladium loading of 10 −4 mol % and the CSM crosscoupling to be carried out at 10 −6 mol %, thus resulting in catalytic turnovers of 10 5 and 10 7 , respectively. Relative comparison of the pincer complex with conventional palladium precursors Pd(OAc) 2 and PdCl 2 (PPh 3) 2 shows the efficiency and robustness of the pincer complex in effecting higher catalytic activity at low palladium loadings.
Green Chemistry, 2017
Recyclable and commercially available Pd/C catalyzes the phenoxycarbonylation reaction using N-fo... more Recyclable and commercially available Pd/C catalyzes the phenoxycarbonylation reaction using N-formylsaccharin as a CO surrogate in propylene carbonate as an environmentally benign and sustainable polar aprotic solvent under co-catalyst free, ligand free and additive free conditions.
European Journal of Organic Chemistry, 2017
This work documents the first Pd/C catalyzed carbonylative Suzuki-Miyaura cross-coupling of aryl ... more This work documents the first Pd/C catalyzed carbonylative Suzuki-Miyaura cross-coupling of aryl iodides using Nformylsaccharin as a CO surrogate. As compared to previous reaction protocols which make use of toxic and hazardous solvents, the reaction could be advantageously carried out in propylene carbonate as an environmentally benign and sustainable polar aprotic solvent. A range of biaryl ketones could be synthesized under co-catalyst free, additive free and ligand free conditions including (4-methoxyphenyl)(3,4,5-trimethoxyphenyl)methanone, an antineoplastic belonging to the phenstatin family. Pd/C could be recycled up to five times under CO surrogacy with only a marginal decrease in catalytic activity. The reaction could also be scaled up to gram scale synthesis.
ChemistrySelect, 2016
Oxime palladacycles- di-μ-chlorobis [5-chloro-2-[(4- chlorophenyl)(hydroxyimino-κN) methyl] pheny... more Oxime palladacycles- di-μ-chlorobis [5-chloro-2-[(4- chlorophenyl)(hydroxyimino-κN) methyl] phenyl-κC] palladium (II) dimer (1) and di-μ-chlorobis [5-hydroxy-2-[1-(hydroxyimino-κN) ethyl] phenyl-κC] palladium (II) dimer (2) provide a phosphine free approach for the synthesis of ynones at low palladium loadings (10−5 mol%) thus resulting in catalytic turnover numbers (TONs) and turnover frequencies (TOFs) of the order of 106. Oxime palladacycle 1 shows TON 587 times and TOF 331 times higher than the best palladium catalyst reported in the literature for the carbonylative cross-coupling between 4-iodoanisole and phenylacetylene as a model reaction. The use of poly (ethylene glycol) as an environmentally benign solvent system allows the recyclability of the oxime palladacycle at low palladium loading up to four times. Further, the oxime palladacycles are advantageous in effecting higher conversion and selectivity at low palladium loadings as compared to conventional palladium precursors- Pd (OAc)2 and PdCl2(PPh3)2
Chemical record (New York, N.Y.), 2016
In this article, we present the progress made in the area of carbonylative CH functionalization,... more In this article, we present the progress made in the area of carbonylative CH functionalization, with special emphasis on arenes and alkanes. The importance of directing group assistance and CH functionalization using CO surrogates is also included. The budding development in the area of transition metal-catalyzed C(sp(3) )H activation makes us feel it necessary to file a summary on the past, as well as current, contributions and a prospective outlook on the transition metal-catalyzed carbonylative transformation of CH bonds, which is the focus of this review.
ACS Omega, 2019
This work documents the first palladium pincer complex-catalyzed carbonylative Sonogashira (CS) a... more This work documents the first palladium pincer complex-catalyzed carbonylative Sonogashira (CS) and carbonylative Suzuki−Miyaura (CSM) cross-coupling. Compared to previous protocols, which employ hazardous and toxic solvents, the aminophosphine pincer complex {[C 6 H 3-2,6-(NHP{piperidinyl} 2) 2 ]Pd(Cl)} (III) catalyzes both the cross-coupling reactions in propylene carbonate, an ecofriendly and sustainable polar aprotic solvent. Advantageously, employing III allows the CS cross-coupling to be carried out at a palladium loading of 10 −4 mol % and the CSM crosscoupling to be carried out at 10 −6 mol %, thus resulting in catalytic turnovers of 10 5 and 10 7 , respectively. Relative comparison of the pincer complex with conventional palladium precursors Pd(OAc) 2 and PdCl 2 (PPh 3) 2 shows the efficiency and robustness of the pincer complex in effecting higher catalytic activity at low palladium loadings.
Green Chemistry, 2017
Recyclable and commercially available Pd/C catalyzes the phenoxycarbonylation reaction using N-fo... more Recyclable and commercially available Pd/C catalyzes the phenoxycarbonylation reaction using N-formylsaccharin as a CO surrogate in propylene carbonate as an environmentally benign and sustainable polar aprotic solvent under co-catalyst free, ligand free and additive free conditions.
European Journal of Organic Chemistry, 2017
This work documents the first Pd/C catalyzed carbonylative Suzuki-Miyaura cross-coupling of aryl ... more This work documents the first Pd/C catalyzed carbonylative Suzuki-Miyaura cross-coupling of aryl iodides using Nformylsaccharin as a CO surrogate. As compared to previous reaction protocols which make use of toxic and hazardous solvents, the reaction could be advantageously carried out in propylene carbonate as an environmentally benign and sustainable polar aprotic solvent. A range of biaryl ketones could be synthesized under co-catalyst free, additive free and ligand free conditions including (4-methoxyphenyl)(3,4,5-trimethoxyphenyl)methanone, an antineoplastic belonging to the phenstatin family. Pd/C could be recycled up to five times under CO surrogacy with only a marginal decrease in catalytic activity. The reaction could also be scaled up to gram scale synthesis.
ChemistrySelect, 2016
Oxime palladacycles- di-μ-chlorobis [5-chloro-2-[(4- chlorophenyl)(hydroxyimino-κN) methyl] pheny... more Oxime palladacycles- di-μ-chlorobis [5-chloro-2-[(4- chlorophenyl)(hydroxyimino-κN) methyl] phenyl-κC] palladium (II) dimer (1) and di-μ-chlorobis [5-hydroxy-2-[1-(hydroxyimino-κN) ethyl] phenyl-κC] palladium (II) dimer (2) provide a phosphine free approach for the synthesis of ynones at low palladium loadings (10−5 mol%) thus resulting in catalytic turnover numbers (TONs) and turnover frequencies (TOFs) of the order of 106. Oxime palladacycle 1 shows TON 587 times and TOF 331 times higher than the best palladium catalyst reported in the literature for the carbonylative cross-coupling between 4-iodoanisole and phenylacetylene as a model reaction. The use of poly (ethylene glycol) as an environmentally benign solvent system allows the recyclability of the oxime palladacycle at low palladium loading up to four times. Further, the oxime palladacycles are advantageous in effecting higher conversion and selectivity at low palladium loadings as compared to conventional palladium precursors- Pd (OAc)2 and PdCl2(PPh3)2
Chemical record (New York, N.Y.), 2016
In this article, we present the progress made in the area of carbonylative CH functionalization,... more In this article, we present the progress made in the area of carbonylative CH functionalization, with special emphasis on arenes and alkanes. The importance of directing group assistance and CH functionalization using CO surrogates is also included. The budding development in the area of transition metal-catalyzed C(sp(3) )H activation makes us feel it necessary to file a summary on the past, as well as current, contributions and a prospective outlook on the transition metal-catalyzed carbonylative transformation of CH bonds, which is the focus of this review.