Stannous Chloride As A Low Toxicity And Extremely Cheap Catalyst For Regio-/Site-Selective Acylation With Unusually Broad Substrate Scope

This work reports stannous chloride (SnCl2)-catalyzed regio-/site-selective acylation with unusually broad substrate scope. In addition to 1,2- and 1,3-diols and glycosides containingcis-vicinal diol, the substrate scope also includes glycosides withoutcis-vicinal diol. For such a substrate scope, usually, only methods using stoichiometric amounts of organotin reagents can lead to the same protection pattern with high selectivities and highly isolated yields (84-97% in most cases). Therefore, SnCl2, as a low toxicity and extremely cheap reagent, should be the best catalyst for regio-/site-selective acylation compared with any previously reported reagents.