tert-Butyl ester
= tert-Butyl ester
A <tert-Butyl ester> contains the group $\mathrm{R-C(=O)-OC(CH_3)_3}$. Its bulky alcohol-derived group differs from the smaller group in a <methyl ester>.
A <tert-Butyl ester> can protect a <carboxylic acid> during a synthesis and then be cleaved under suitable acidic conditions. This is an example of selecting a <protecting group> by the conditions required for both its survival and removal.