Chemoselective and diastereodivergent synthesis of new spirooxindolo-pyrrolizidines and pyrrolidines stemming from unsymmetrical 1, 3-bis(arylidene)tetral-2-ones: a combined experimental and theoretical study. (29th September 2022)

• Record Type: Journal Article
• Authors: Gazzeh, Houda; Rouatbi, Fadwa; Chniti, Sami; Askri, Moheddine; Knorr, Michael; Strohmann, Carsten; Golz, Christopher; Lamsabhi, Al Mokhtar
• Is Part Of: New journal of chemistry. Volume 46:Number 40(2022)
• Page Start: 19198
• Page End: 19212
• Publication Date: 2022-09-29
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/d2nj03887k
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : An experimental and theoretical study of an efficient one-pot three-components cycloaddition reaction leading to pentacyclic dispiropyrrolizidin/pyrrolidinoxindoles endowed by four contiguous stereogenic centres with moderate to good yields was reported. Abstract : A theoretical and experimental study of a three-component one-pot cycloaddition reaction involving unstabilized azomethine ylides and unsymmetrical exocyclic dienones featuring a tetralone core was performed. Two new families of highly substituted dispirooxindolo-pyrrolizidine/pyrrolidines were obtained with moderate to good yields. To rationalize the origin of the reactivity difference between the two exocyclic double bonds of the starting dienones, a topological QTAIM (Quantum theory of Atoms in Molecules) analysis study has been performed. To rationalize the observed regio- and stereoselectivity of the [3+2] cycloaddition, a computational approach was realized by means of density functional theory (DFT) at the B3LYP/6-311G(d, p) level of theory. The calculations corroborate the experimental findings. It was demonstrated that the double bond located at the 3-position of the enone scaffold is more reactive than its analogue at the 1-position and that the aforementioned reaction occurs in a chemoselective manner through a two-step mechanism. Moreover, it progresses under kinetic control to offer a mixture of two dispirooxindolo-pyrrolidines/pyrrolizidines with a high diastereomeric excess. The relative stereochemistry of derivative 4k was confirmed by an X-ray crystallography study. The intermolecular N–H–O hydrogen bonding occurring in the difluorinated spiro-compound 4k has been investigated by Hirshfeld surface analysis. Furthermore, the electronic absorption and fluorescence properties of several derivatives have been studied.