K10 montmorillonite catalyzed C–C bond formation of aromatic secondary alcohols and alkynes: A green and convenient approach to β-aryl ketones under solvent-free conditions

Abstract

The synthesis of β-aryl ketones from aromatic alkynes and secondary alcohols catalyzed by heterogeneous K10 montmorillonite via C–C bond formation has been described. This method presents a green and facile approach for the synthesis of various β-aryl ketones. It is relevant to mention that this approach proceeds under solvent free conditions without any usage of further additives and immobilizations. Effect of amount of catalyst, reaction temperature and time on the yield of product have been investigated by using K10 montmorillonite. This process is sustainable and exhibiting good compatibility among a range of various aromatic alkynes and secondary alcohols affording moderate to excellent yields. The presence of unique layered structure as well as strong acidic sites in the K10 montmorillonite might be responsible for the formation of β-aryl ketones and these acidic sites were validated by temperature programmed desorption of ammonia (NH3-TPD) studies. Based on the in situ HRESI-MS and control experiments a tentative mechanism for the formation of β-aryl ketones using K10 montmorillonite as a catalyst was proposed. The efficacy and viability of scale-up of the present catalytic system was demonstrated with gram scale experiments (up to 10 g scale).