dimethyl (R,E)-2-(4-(tert-butyldimethylsilyl)-4-hydroxybut-2-en-1-yl)malonate

dimethyl (R,E)-2-(4-acetoxy-4-(tert-butyldimethylsilyl)but-2-en-1-yl)malonate

dimethyl 3-oxopropane-1,1-dicarboxylate