PBGroup

Dr. Prabal Banerjee

Associate Professor
Department of Chemistry
Nangal Road, Rupnagar-140001 Punjab.
Email: prabal@iitrpr.ac.in
Alt. Email: banprabal@gmail.com
Phone: 01881-242112
Fax: 01881-223395

2022: we congratulate Arijit Hazra and Tanmay Kanji for their accepted article in The Journal of Organic Chemistry.

2022: Glad to see our research “Direct Synthesis of Paracetamol via Site-Selective Electrochemical Ritter-type C-H Amination of Phenol” highlighted in Organic Chemistry Portal. Link: https://www.organic-chemistry.org/abstracts/lit8/383.shtm

2022: We congratulate Dr. Debarshi Saha for winning best poster award in FICS(Frontiers in Chemical Science) 2022 & Dr. Irshaad Maajid Taily for winning best poster award in Chemical Science symposium 2022.

2022: Congratulations to  Rakesh Kumar and Irshad Maajid Taily for the accepted article in Chemical Communication.

Electrochemical sulfinylation of phenols with sulfides: a metal- and oxidant-free cross-coupling for the synthesis of aromatic sulfoxides

Rakesh Kumar, Irshad Maajid Taily and Prabal Banerjee

The site-selective C–H functionalization of arenes is of indisputable importance in organic chemistry. Herein, we have demonstrated an electrochemical regioselective oxidative cross-coupling towards the direct C(sp²)–H sulfinylation of phenols with sulfides under mild reaction conditions. The designed methodology furnished aryl sulfoxides in good to moderate yields under exogenous metal and oxidant-free conditions. Moreover, the exploitation of traceless electrons to carry out the tandem site-selective oxidative aryl chalcogenation is the striking feature of this methodology.

Switchable Reactivity of Cyclopropane Diesters toward (3 + 3) and (3 + 2) Cycloadditions with Benzoquinone Esters

Navpreet Kaur, Pankaj Kumar, Arijit Hazra, and Prabal Banerjee

Herein, we describe an unprecedented (3 + 3) cycloaddition reaction of the donor–acceptor cyclopropanes with quinone esters toward the construction of chroman scaffolds in moderate to good yields. Interestingly, the strategy is also adjustable toward a (3 + 2) cycloaddition by just switching the Lewis acid to furnish benzofuran scaffolds. Based on the choice of Lewis acid used, the same set of precursors has been used to deliver the benzopyran and benzofuran derivatives

 Accessing Complex Tetrahydrofurobenzo-Pyran/Furan Scaffolds via Lewis-Acid Catalyzed Bicyclization of Cyclopropane Carbaldehydes with Quinone Methides/Esters 

Navpreet Kaur, Pankaj Kumar, Shiv Dutt, and Prabal Banerjee

Herein, we report a straightforward one-pot synthesis of tetrahydrofurobenzopyran and tetrahydrofurobenzofuran systems via an in situ ring-expansion of the cyclopropane carbaldehydes followed by a [2 + n] cycloaddition with the quinone derivatives. The transformation not only unveils a new reaction mode of cyclopropane carbaldehydes with quinone methides/esters, but also promotes a step-efficient diastereoselective route to the sophisticatedly fused oxygen tricycles that can be further dehydrogenated to access the valued dihydro-2H-furo[2,3-b]chromene frameworks.

?,ß-Unsaturated Carbonyls for One-Pot Transition-Metal-Free Access to 3,6-Dihydro-2H-pyrans 

Pankaj Kumar, Navpreet Kaur, Rakesh Kumar, and Prabal Banerjee

An efficient protocol has been developed for accessing mono, di, and trisubstituted 3,6-dihydro-2H-pyran derivatives by simply subjecting ?,?-unsaturated carbonyls to the carefully optimized Corey-Chaykovsky reaction conditions. The strategy provides selectively substituted dihydropyran derivatives in good to excellent yields with a broad substrate scope under very mild reaction conditions. Easy transformation of the final 3,6-dihydro-2H-pyran to the valued 5,6-dihydro-2H-pyran-2-one and tetrahydro-2H-pyran derivatives expanded the scope of this methodology to diverse oxacycles. Further, the developed strategy also found application in a two-step route to racemic goniothalamin, which is widely studied for its cytotoxic behaviour.

Electricity mediated [3+2]-cycloaddition of N-sulfonylcyclopropanes with olefins via N-centered radical intermediates: access to cyclopentane analogs

Debarshi Saha, Irshad Maajid Taily, Nakshatra Banerjee and Prabal Banerjee

An external oxidant free electrochemical strategy is designed towards the b-scission of strained C–C bonds in cyclopropylamine. Moreover, the mechanistic studies ascertained that the methodology encompasses the N-center radical (NCRs) route and provides access to di- or tri-substituted cyclopentane analogs.

Direct Synthesis of Paracetamol via Site-Selective Electrochemical Ritter-type C-H Amination of Phenol

Irshad Maajid Taily, Debarshi Saha and Prabal Banerjee

The synthesis of paracetamol still relies on multistep protocols involving the utilization of a stoichiometric amount of oxidizing/reducing or other corrosive agents. Herein we report a regioselective electrochemical Ritter-type reaction at the C(sp2)?H of unprotected phenol toward the environmentally benign and direct synthesis of paracetamol. The reaction proceeds under exogenous oxidant- and catalyst-free conditions. The protocol is scalable, can be deployed to a variety of phenols, and offers a sustainable alternative for the synthesis of paracetamol.