On the important transition of sugar-based surfactant as a microreactor for C-S coupling in water: From micelle to vesicle

Abstract

A reversible, temperature-induced micelle-to-vesicle transition of a sugar-based pseudogemini surfactant (C11D12) was employed for copper-catalyzed C-S coupling in water. The phase behavior and morphology of the C11D12 aqueous solution were investigated by DLS and cryo-TEM. The aggregates undergo a series of transitions upon increasing the temperature: spherical micelles were initially transformed into large vesicles, but they eventually transformed into smaller vesicles. The vesicular catalytic protocol accommodates an excellent substrate scope with moderate to high yields. The mechanisms of temperature-induced aggregate transition and vesicular catalysis were elucidated by experimental results and DFT calculations. It was revealed that the charge layer of the vesicle grants stronger nucleophilicity to the PhSO2-Cu-D12Ga intermediate. Furthermore, the aqueous reaction medium can be recycled and reused several times after easily separating the precipitated product.