Unravelling copper catalyzed synthesis of organochalcogenides: A computational journey

Bhattacharya, Anurag (2025) Unravelling copper catalyzed synthesis of organochalcogenides: A computational journey. Masters thesis, Indian Institute of Science Education and Research Kolkata.

Text (MS Dissertation of Anurag Bhattacharya (20MS092)) 20MS092_Thesis_file.pdf - Submitted Version Restricted to Repository staff only Download (1MB)

Abstract

Transition metal catalysed synthesis of unsymmetrical organochalcogenides have become extremely important in modern times due to their wide range of applications in industries and pharmaceuticals. In this thesis, the copper-catalysed conversion of dichalcogenides to monochalcogenides using aryl or alkylboronic acids was investigated using density functional theory calculations. Initially, copper(I) bipyridine iodide complex converts to copper(I) bipyridine hydroxide complex with the help of DMSO-water cluster, which serves as the active catalyst in the reaction. After that, the active copper(I) bipyridine hydroxide catalyst undergoes transmetalation in the presence of organoboronic acid which is the rate-determining step in the reaction mechanism with an energy barrier of 26.5 kcal mol-1. Then, the complex reacts with dichalcogenide and undergoes oxidative addition and reductive elimination with an energy barrier of 21.3 kcal mol-1, leading to the release of the first molecule of product and the Cu-bpy-SPh complex. The copper(I)-bpy-SPh complex then undergoes oxidation in the presence of oxygen molecule leading to the formation of Copper(II) complex with an energy barrier of 11.6 kcal mol-1. The copper (II) complex then undergoes the second transmetalation, followed by disproportionation and reductive elimination which gives us the second molecule of product i.e. unsymmetrical organochalcogenides and goes back to the active copper(I) bipyridine hydroxide catalyst. The DMSO-water cluster was extremely essential for obtaining a high yield of the reaction and to convert the inactive copper(I) bipyridine iodide catalyst to active copper (I) bipyridine hydroxide catalyst. Our computational results were also compared with the experimental substrate scope reported, and a good consistency in reactivity trends was observed. This computational study provides further and detailed insights into the conversion of dichalcogenide to monochalcogenide and offers a foundation for developing and planning similar substrate for the reaction.

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