Monocatenary, branched, double-headed and bolaform surface active carbohydrate esters via photochemical thiol-ene/-yne reactions

An original and versatile method for the synthesis of a range of novel mannose-based surfactants was developed via metal-free photo-induced thiol-ene/-yne “click” reactions. This light-mediated hydrothiolation reaction involving a thiolated mannose was successfully applied to terminal and internal alkenes, dienes and alkynes, leading to monocatenary, branched, double-headed and bolaform amphiphilic carbohydrate esters,respectively. A surface activity study showed that these new compounds possess valuable properties and display specific behavior at the air-water interface. It also demonstrated the greater flexibility of the thioether moiety in the spacer of the surfactants produced via a thiol-ene reaction in comparison withthe triazole heterocyclic rings in similar glucose-based surfactants synthesized elsewhere by the alkyne-azide 1,3-dipolar addition.