ArCHO \text {ArCHO}ArCHO
(CH3)3C−CHO\left(\mathrm{CH}_{3}\right)_{3} \mathrm{C}-\mathrm{CHO}(CH3)3C−CHO
H−CHO\mathrm{H}-\mathrm{CHO}H−CHO
CH3−CHO\mathrm{CH}_{3}-\mathrm{CHO}CH3−CHO