The reactivity of (E)-1-(tert-butyldimethyl)silyloxy-3,3-bis(tributylstannyl)propene 1 as potential 1,3 dianion equivalent has been investigated. Condensation with aldehydes 4a-h, in presence of BF3OEt2, afforded in high yields the mono-protected diols 5a-h exhibiting an exclusive E configuration of the vinyltin residue. Good to high syn selectivities have been measured, in agreement with an S-E' addition mechanism. Further transformation of the resulting vinyltin moiety of these diols into various functionalities has been successfully tested. (C) 1997 Elsevier Science Ltd.