Carbonyl–Allene Metathesis of S-Allenyl-α-oxo- S , S/N , S -ketene Acetals: A Thermally Driven Intramolecular Tandem [2 + 2] Cycloaddition–Retro-Cyclization

Organic Letters 2026

View at publisher
Authors: Malkeet Singh, Malkeet Singh, Saurabh Singh, Nimisha Gupta, Ashvani K. Singh, M. Dhaneshwar Singh, M. Dhaneshwar Singh
DOI: 10.1021/acs.orglett.5c05163
Cited by: 1
References: 56

Abstract

Carbonyl–allene metathesis (CAM) represents an emerging class of bond-reorganizing transformations with significant synthetic potential. Here, we report a thermally controlled, catalyst-free intramolecular CAM reaction demonstrated via a tandem [2 + 2] cycloaddition and retrocyclization of S-allenyl-α-oxo- S, S -/ N, S -ketene acetals. Control experiments and kinetic and DFT studies indicate the reaction involved an asynchronous concerted cycloaddition between the carbonyl and allene moieties, forming an oxetane intermediate, which subsequently undergoes retro-cyclization to afford 2,4-disubstituted thiophene derivatives.

Fields of Study & Subjects

Synthetic Organic Chemistry Methods Catalytic Alkyne Reactions Carbon dioxide utilization in catalysis

Publication details

Journal / source
Organic Letters
Publisher
American Chemical Society (ACS)
Volume
28
Issue
4
Pages
1355–1360
Publication date
14 January 2026
Language
EN