The reaction of ketene alkylsilyl acetale with ethyl propiolate in the presence of TiCl, led to intermediates whose reactivity was studied with electrophiles such aa H20, D20, NBS, NCS, and PhSeCl to form glutaconate derivativea. Ekcept in the case of the dimethylketene trimethylsilyl acetal, for which the reaction waa stereospecific, with other ketene acetals the aelectivity waa lower. Similar results were observed in the reaction of these titanium ...