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Biography

Aankhi is a Ph.D Scholar at the Department of Chemistry, Indian Institute of Technology, Kharagpur, since September, 2020. Under the supervision of Dr. Ganesh Venkataraman, her research revolves around the difunctionalization of unsaturated compounds using transition-metal catalysis. She was awarded the Prime Minister's Research Fellowship during May 2020 cycle.

She graduated from Lady Brabourne College, Kolkata with Bachelor's in Chemistry (Hons.) (Calcutta University), before joining IIT KGP for completing her Master's. Her M.Sc project on synthesis and reactivity of enediynes was supervised by Prof. Amit Basak.

For a detailed CV, have a look at aankhi's CV!

Research Interest

Asymmetric Metal-Mediated Difunctionalization of Unsaturated Systems

Asymmetric multicomponent reactions have transformed the outlook of approach to complex natural products, pharmaceuticals, and agrochemicals. The approach to complex molecular skeletons has transformed with a growing arsenal of efficient synthetic methodologies. Metals play an important role in this due to their diverse reactivity at their various oxidation states. Our group focuses on developing new, interesting multi-functionalization reactions utilizing this diversity.

We propose an asymmetric metal-mediated difunctionalization of alkynes and their subsequent application in total synthesis of natural products. The primary motivation of this proposal is to facilitate reductive coupling with electrophiles by coordination with low-valent, earth-abundant and highly potent transition-metal like Ni.

Literature Background

Alkynes are innately potent in increasing the complexity of a system in a single step in coupling reactions. The primary motivation of this proposal is to facilitate reductive coupling with electrophiles by coordination with low-valent transition metals. The coordination could ultimately enhance the nucleophilicity of the sp-hybridized alkyne carbon. Heck type coupling with various organometallic reagents can then be made feasible by the resultant oxidized metal center.

Montgomery and Jamison have studied the reductive coupling of alkynes and aldehydes. However, these protocols were either limited by substrate-dependent regio- and enantioselectivities or narrow scope in general. Only two reports on enantioselective three-component coupling have accessed tetrasubstituted olefins restricted to the introduction of methyl group as the third component. The absence of systematic studies in this chemistry has inspired us to embark on this field and aim for three-component coupling on various systems.

The catalyst for choice for such transformations is an extremely air-, moisture-, and heat-sensitive Ni⁰source- commercially available Ni(cod)_2.Thus, this methodology depends on stringent glove-box infrastructure, which involves time-consuming, error-prone, and tedious weighing procedures. To address this limitation, we propose to assemble the reductive coupling of alkynes and aldehydes on the benchtop, making the methodology more operationally simple, accessible, and feasible for execution.

Research Proposal

Glove-box free assembling of reductive coupling between aldehydes and alkynes on benchtop

glove-box free methodology assembled on benchtop broader substrate scope

Research Progress

1) Benchwork Oct, 2021 - Preparation of air-, moisture-, and bench-stable Ni(0) catalyst - Ni(COD)(DQ) from literature procedure (Angew. Chem. Int. Ed. 2020, 59, 7409 . (DQ = Duroquinone)

2) Ongoing investigation of scope of reductive coupling wih this catalyst.

NMR ( ¹H NMR, CDCl₃) -Ni(COD)(DQ)

2) WORK FROM HOME – Sept. 2020 to Sept. 2021

We did computational studies on stereoselective functionalization of sulfinyl dienes.

Colomer and co-workers reported a stereo-controlled cascade functionalization of α-hydroxy sulfinyl diene involving conjugate addition of nucleophile followed by protonation (Chem. Eur. J. 2020, 26, 4620). We conducted DFT studies on the optimized geometries, IR stretching frequencies, potential energy scans, and single point energies of all species involved in the reaction including substrates, products, intermediates, and in-between. Ongoing work on comparison and identification of the favorable reaction pathway out of all mechanistic possibilities.