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 containing cis-vicinal diol, the substrate scope also includes glycosides without cis-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.