[3+2] regioselective annulation reaction of 2-arylidene-1, 3-indandiones towards synthesis of spirocyclopentenes: understanding the mechanism of γ-attack vs. α-attack using DFT studies. Issue 61 (1st December 2021)

• Record Type: Journal Article
• Authors: Anwar, Shaik; Lin, Li-Tzu; Srinivasadesikan, V.; Gudise, Veera Babu; Chen, Kwunmin
• Is Part Of: RSC advances. Volume 11:Issue 61(2021)
• Page Start: 38648
• Page End: 38653
• Publication Date: 2021-12-01
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d1ra07165c
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : A [3+2] annulation protocol for the construction of functionalized spirocyclopentenes utilizing 1, 3-indanedione derived benzylidene-1, 3-indanedione and ethyl-2, 3-butadienoate at room temperature was developed. Abstract : A regioselective [3+2] cyclisation reaction between 2-arylidene-1, 3-indanedione and ethyl 2, 3-butadienoate catalysed by triphenylphosphine has been demonstrated to synthesize functionalised spirocyclic cyclopentenes. The reaction tolerated various electron-rich and electron-deficient aryl substituted 2-arylidene-1, 3-indanediones with high to excellent chemical yields (up to 99%) and moderate to good regioselectivity (up to 5 : 1). DFT studies have also been carried out to understand the regioselective nature of this reaction. The results of Frontier molecular orbital calculations and the activation energy ( E a ) favour the formation of compound 3a via γ-attack compared to that of 4a via α-attack.