Regio and Stereochemical Considerations of 1,3-Dipolar Cycloadditions; Aryl Nitrile Oxides to Aryl Cinnamamides
Date of Award
Campus Access Dissertation
Doctor of Philosophy (PhD)
1,3-Dipolar cycloadditions are a versatile method for the formation of five membered heterocyclic rings. 1,3-dipolar cycloaddition is defined as the thermally allowed [π4s + π2s] cycloaddition of 1,3-dipole and dipolarophile, in which two π-electrons of the dipolarophile and four electrons of the 1,3-dipole contribute in a pericyclic manner to form an uncharged five-membered ring. Isoxazolines, formed from the cycloaddition of nitrile oxides to dipolarophiles, are important heterocycles as a precursors or by themselves for various biological activities. Nitrile oxides as the 1,3-dipole affords a very flexible platform that can yield a wide variety of isoxazolines. Due to the concerted mechanism of the reaction, chiral centers with nitrogen and oxygen functionalities are relatively easy to form. Easy cleavage of the N-O bond when required can form various intermediates and hence a flexible method to enter into acyclic compounds as well.
In this study, the formation of regioisomers of three aryl nitrile oxides to a series of aryl cinnamamides is explored. Electron donating and electron withdrawing substituents on the cinnamamides and benzonitrile oxides are used to investigate the effect of molecular polarity on the yield of the cycloaddition. Cycloaddition of the benzonitrile oxides with selected monosubstituted and disubstituted esters and amides are also investigated for comparison.
Pal, Reshma, "Regio and Stereochemical Considerations of 1,3-Dipolar Cycloadditions; Aryl Nitrile Oxides to Aryl Cinnamamides" (2015). Graduate Doctoral Dissertations. 216.
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