E-BETA-FORMYLVINYL AND Z-BETA-FORMYLVINYL SYNTHONS FROM 1-TRIBUTYLSTANNYL-3,3-DIETHOXY-PROP-1-ENE VIA CROSS-COUPLING WITH ACID-CHLORIDES

The easily prepared and stored E-1-tributylstannyl-3,3-diethoxy-prop-1 -ene 1E reacts with acyl chlorides in DMF in the presence of PdCl2(MeC N)2 to give the expected 1,4-ketoacetals (E isomers). Similarly cross coupling of 1E with tosyl chloride performed in THF in the presence of Pd(PPh3)4 affords the E-beta-diethoxymethylvinylsulphone whose metall ation with MeLi, LiBr generates a beta-formylvinylanion equivalent wit h the anionic centre in a cis relationship relative to the diethoxymet hyl group.