(CH,), CHCO, CH,+(CHBO)* PH v VI spectrum (neat): 3.62 (doublet, JHp= 11.5 Hz, CH, O), 1.67 and 2.07 (doublets, JHp= 2.5 and 3.0 Hz, vinyl methyl groups), 1.19 (doublet, JHH= 7.0 Hz, isopropyl methyls), and 2.66 ppm (multiplet, methine hydrogen). The intensities of the pmr absorptions are appropriate for the structure assignment 111. Important ir bands (neat film) occur at 1750 (s), 1650 (w), and 1265 (s) cm-l. Acid hydrolysis of I11 gave 1.6 moles ...