Stereoselective synthesis of functionalised triol units by SnCl4 promoted allylation of α-benzyloxyaldehydes: crucial role of the stoichiometry of the Lewis acid

Enantiomerically pure syn–anti and syn–syn configured triol units are efficiently synthesized by the SnCl4 mediated allylation of chiral α-benzyloxyaldehydes with the uniquely functionalised allylstannane . Remarkably, the stereochemistry of the adducts is solely governed by the amount of Lewis acid employed.