Research Interest

Research in our group involves the development of novel strategies for the synthesis of medicinally active heterocycles. Our work is mainly focused on the applications of the well-known Bestmann-Ohira reagent in the synthesis of nitrogen heterocycles.

The reactions involving the Bestmann-Ohira Reagent

The Bestmann–Ohira reagent (BOR, dimethyl α-diazo-β-oxopropylphosphonate) is a well-known reagent for the homologation of aldehydes to terminal alkynes under mild conditions and this reagent is particularly useful for the homologation reactions of delicate substrates. Later, notable reports by Namboothiri and Smietana, as well as recent advances, have shown that the dimethyl (diazomethyl) phosphonate anion (DAMP) generated in situ from BOR could be employed as a versatile 1,3-dipole for the synthesis of phosphonylpyrazoles from numerous electrophilic olefins.1 Yet, despite the significant progress achieved in this field, most reactions require pre-functionalized olefins to generate the desired pyrazole derivatives, and a direct utilization of commercially available or readily accessible substrates in a domino-multicomponent reaction to effectively generate functionalized pyrazoles still remains unexplored. We have recently developed an attractive protocol for the regioselective synthesis of densely functionalized pyrazoles and spiro-oxindoles-pyrazolines employing BOR as a 1,3-dipolar species in a domino-pathway. Furthermore, an efficient strategy has been uncovered demonstrating for the first time that BOR can be employed in a domino multicomponent reaction involving aldehydes and amines for the diastereoselective synthesis of 1,4,5-trisubstituted-1,2,3-triazolines.2 Moreover, a domino-HWE homologation/1,3-dipolar cycloaddition/oxidation sequence involving BOR has been disclosed for the regioselective synthesis of densely functionalzed phosphonylpyrazoles.

Recent publications

image01 Ahamad, S.; Kant R.; Mohanan, K. Org. Lett. 2016, 18, 280.
image01Gupta, A. K.; Ahamad, S.; Gupta, E.; Kant R.; Mohanan, K. Org. Biomol. Chem. 2015, 13, 9783.
image01Ahamad, S.; Gupta, A. K.; Kant R.; Mohanan, K. Org. Biomol. Chem. 2015, 13, 1492.