Metal-free functionalization of SQs: a case of chemoselectivity and what ball-milling has got to do with it?

Abstract

A new simple, metal-free modification of mercapto-substituted silsesquioxane (SQ-SH) with α,β-unsaturated aldehydes is presented. Depending on the conditions used, the products of thioesterification or sulfa-Michael addition (SMA) are selectively obtained, following the green chemistry rules. For the first time, ball milling has been used in the solvent-free synthesis of sulfur-functionalized SQs. The proposed methodologies use commercially available reagents and lead to novel classes of SQ-based materials of great potential in industrial and synthetic applications.