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Home  »  Colloquium   »   N-Heterocyclic Carbene Complexes of Cobalt: Application in Catalytic Borylation Reaction

N-Heterocyclic Carbene Complexes of Cobalt: Application in Catalytic Borylation Reaction

colloquium

Title : N-Heterocyclic Carbene Complexes of Cobalt: Application in Catalytic Borylation Reaction.
Speaker : Prof. Geetharani K, Department of Inorganic and Physical Chemistry, IISc Bangalore.
Date : 10/02/2021, 05:30 PM , Online Mode.

 

 

 

Abstract:

Organoboronates have been well recognized as indispensable building blocks in organic synthesis. Their importance in current scenario of chemical, medicinal and material science is manifested by its ubiquity in these fields, mainly because these stable esters can be selectively transformed into wide number of functionalities by vast number of available protocols.1 However, most of their efficient synthetic routes rely on heavy metal based catalysts such as Pd, Rh, Ir etc. which suffers from inherent toxicity, cost and sustainability concerns.2 This obviously put forth the needful for the development of catalytic systems based on earth abundant metals like Mn, Fe, Co etc. We have developed N-heterocyclic carbene supported cobalt catalyst for the synthesis of aryl and alkyl boronic esters using cheap as well as challenging precursors, such as aryl chlorides3 and substituted alkenes.4 The cobalt-complex Co(IMes)2Cl2 in presence of base and bis(pinacolato)diboron (B2pin2) affords aryl halide borylation with good to excellent yields under mild reaction conditions. Mechanistic investigation verifies the involvement of in situ generated reduced complex Co(IMes)2Cl as an active catalyst which undergoes Co(I)-Co(III) catalytic cycle. The potential of Co(I) complex, Co(IMes)2Cl to undergo oxidative addition was further utilized in hydroboration of substituted vinyl arenes with HBpin in an unusual Markovnikov fashion. We have also demonstrated the first cobalt-mediated cross-coupling of alkyl electrophiles with a diboron reagent to provide a wide range of alkyl boronic esters. 5 The key results will be discussed.

 

 

 

(1) Boronic Acids: Preparation and Applications in Organic Synthesis, Medicine and Materials; 2nd ed.; Hall, D. G., Ed.; Wiley-VCH: Weinheim, 2011.

 

(2) (a) Mkhalid, I. A. I.; Barnard, J. H.; Marder, T. B.; Murphy J. M.; Hartwig, J. F. Chem. Rev. 2010, 110, 890-931. (b) Neeve, E. C.; Geier, S. J.; Mkhalid, I. A. I.; Westcott, S. A.; Marder, T. B. Chem. Rev. 2016, 116, 9091-9161.

 

(3) Verma, P. K.; Mandal, S.; Geetharani, K. ACS Catal. 2018, 8, 4049-4054.

 

(4) Verma, P. K.; Sethulekshmi, A. S.; Geetharani, K. Org. Lett. 2018, 20, 7840-7845.

 

(5) Verma, P. K.; Sujit Prasad, K.; Varghese, D.; Geetharani, K. Org. Lett. 2020, 22, 1431-1436.

 

 

Research Interests

 

  • Development of Base Metal Catalysts for Borylation Reactions.

 

  • Catalytic Additions of Boron-Element to Unsaturated Organic Molecules

 

  • Transition Metal Based Frustrated Lewis Pairs: Synthesis and Applications

 

  • Multiply Bonded Main Group Compounds and its Reactivity

 

Work Experience

 

  • Nov. 2015-Jan. 2016: Assistant Professor, Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata

 

  • Feb. 2015-Aug. 2015: Postdoctoral fellow at University of Würzburg, Germany with Prof. H. Braunschweig.

 

  • Feb. 2013-Jan. 2015: Alexander von Humboldt (AvH) postdoctoral fellow at University of Würzburg, Germany with Prof. H. Braunschweig.

 

  • Sep. 2012-Jan. 2013: Postdoctoral fellow at University of Würzburg, Germany with Prof. H. Braunschweig.

 

Academic Qualifications

 

  • July 2007-June 2012: Ph.D. (Chemistry) Indian Institute of Technology Madras, India Thesis Supervisor: Prof. Sundargopal Ghosh, Indian Institute of Technology Madras, India

 

  • June 2005-June 2007: Master of Science (Chemistry), Madurai Kamaraj University, Tamilnadu, India

 

  • June 2002-May 2005: Bachelor of Science, Madurai Kamaraj University, Tamilnadu, India

 

Fellowships and Awards

 

  • 2020: SERB- Women Excellence Award (Presented by the President of India)

 

  • 2019: NASI-Young Scientist Platinum Jubilee Award.

 

  • 2019: Young Scientist Medal, Indian National Science Academy (INSA).

 

  • 2018: Young Associate, Indian Academy of Sciences.

 

  • 2015: DST Inspire Faculty Award.

 

  • 2013: Alexander von Humboldt postdoctoral fellowship, Germany.

 

  • 2013: “Werner prize”- Best Ph.D. thesis in Inorganic and Analytical Chemistry, Indian Institute of Technology Madras, India.

 

  • 2008: Qualified the Joint CSIR-UGC National Eligibility Test.

 

  • 2007: Qualified Graduate Aptitude Test in Engineering (GATE–2007).

 

Memberships of Journal Editorial Boards

  • 2020: Early Career Advisory Board: Chemistry – An Asian Journal, Asian Chemical Editorial Society (ACES), Wiley-VCH GmbH, Weinheim