1,3‐Dipolar Cycloaddition Reactions Leading to the Synthesis of New 2,3,5‐Triaryl‐4H,2,3,3a,5,6,6a‐hexahydropyrrolo[3,4‐d]isoxazole‐4,6‐diones

Abstract

Cycloaddition of C,N‐diphenylnitrones 1 to N‐aryl maleimides 2 afforded two diastereomeric isoxazolidines with high selectivity. The structure and steric configuration of the adducts have been assigned on the basis of 1H NMR, 1H NMR COSY, 13C NMR and IR spectroscopy. The π–π stacking interactions between maleimide's and nitrone's aromatic rings during the 1,3‐dipolar cycloaddition were assumed to control the exo–endo selectivity of the reaction. Thus, the exo–endo ratio depends upon the position of the substituent present on the C‐phenyl ring of the C,N‐diphenylnitrones.

High diastereoselectivity induced by intermolecular hydrogen bonding in [3 + 2] cycloaddition reaction: experimental and computational mechanistic approaches

“…Endo‐E transition state is another possible transition state on the reaction route to the cis ‐diastereomer (Figure ). The secondary orbital interactions , noncovalent attractive interactions between the N ‐bonded aromatic rings belonging to the E‐ nitrone and the maleimide can cause the reaction to proceed via this transition state . There are large numbers of studies that support cycloaddition reactions via E ‐nitrones .…”

“…Cycloaddition reactions between acyclic/cyclic nitrones (azomethine‐ N ‐oxides) and N ‐aryl substituted maleimides have been studied extensively in the last 2 decades . As is well known aldonitrones may have 2 configurations that may interconvert.…”

Synthesis and Antimicrobial Evaluation of New Pyrrolo-isoxazolidine Derivatives

“…The most significant aspect of the above 1,3-dipolar cycloaddition reaction is their capability to generate the three adjoining stereogenic centres through the regioselective and stereoselective way [12]. These aspects have attracted the much attentions of the researchers to utilize these reactions in the formation of five membered heterocyclic products which are realized in the cis and trans diastereomeric forms [13,14].…”

“…In the literature 1,3-dipolar cycloaddition reactions of N-aryl-maleimide with variety of nitrones have been fully exploited bearing the various substituent upon the N-aryl group of maleimide as well as on the N-imino aryl/heteroaryl rings of the nitrone [12][13][14]31]. Thus, the present study has been taken up with a view to fill the gap in the literature and to explore the antimicrobial studies of final heterocyclic products [7].…”