Short synthesis of phenylpropanoid glycoside grayanoside-A and analogues

A short synthesis of phenylethyl glycosides grayanoside-A 1, 2 and analogues 3–4 in high 43–65% overall yields is described. The main synthetic step involved regioselective O-6 acylation of unprotected 2-phenylethyl-β-D-glucoside 7 with cinnamoyl chlorides 8a-d using Me₂SnCl₂as catalyst. The acylation at O-6 is regioselective regardless of the type of cinnamoyl chloride used. Protection/deprotection steps of the glucoside core were not necessary. The synthetic route is generally applicable for the synthesis of phenylpropanoid glycoside class of compounds acylated at O-6.