Highly regio- and diastereoselective 3+2]-cycloadditions involving indolediones and alpha,beta-disubstituted nitroethylenes

Rao, Madhuri P and Gunaga, Shubha S and Zuegg, Johannes and Pamarthi, Rambabu and Ganesh, Madhu (2019) Highly regio- and diastereoselective 3+2]-cycloadditions involving indolediones and alpha,beta-disubstituted nitroethylenes. In: ORGANIC & BIOMOLECULAR CHEMISTRY, 17 (42). pp. 9390-9402.

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Abstract

A highly diastereoselective 3 + 2]-cycloaddition strategy involving multiple oxindoles and several alpha,beta-disubstituted nitroethylenes is developed to access tetra-substituted alpha-spiropyrrolidine frameworks. A variety of alpha-amino acids were employed for the first time in order to generate azomethine ylides under thermal conditions, affording regioisomers 13 and 14 merely by changing the alpha-substituents (R = H and substituted carbons) of the alpha-amino acids. The reaction tolerates various sterically demanding, electron-rich and electron-deficient aryl and nitrogen substituents on glycines, oxindoles and nitroethylenes. The operational simplicity, such as the use of a metal-free and non-inert environment, the utilization of non-halogenated solvents and the ease of isolation, adhering to the principles of green chemistry, makes this process attractive for scale-up opportunities. The reaction delivers good yields (80-94%) and diastereoselectivities (up to 98 : 2) in favor of (cis,cis)-spirooxindoles, with opposite regioselectivity compared to beta-nitrostyrenes under identical conditions. Two spiropyrrolidine cycloadducts with unprotected amides exhibited significant activity against Gram-positive MRSA.

Item Type:	Journal Article
Publication:	ORGANIC & BIOMOLECULAR CHEMISTRY
Publisher:	ROYAL SOC CHEMISTRY
Additional Information:	copy right of this article belong to ROYAL SOC CHEMISTRY
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	17 Dec 2019 05:23
Last Modified:	17 Dec 2019 05:23
URI:	http://eprints.iisc.ac.in/id/eprint/63924

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