The trimethysilylated primary Michael adduct of tricarbomethoxymethane and 2-bromo-3- oxo-3-phenylpropeue-1 is shown by 'H NMR experiments and X-ray diffraction studies to possess the structure Z-2. Attempts to prepare the E isomer via the hydrolysis product of Z-2 resulted in, inter alia, an intramolecular alkylation under decarbomethoxylation to give the cyclopropane ester 4.
