content_image/911408.jpg content_image/911407.jpg content_image/911406.jpg
include acetal structure groups, ketal structure groups, and alkoxycarbonyl groups, examples of which are shown below. 

<img src='content_image/911408.jpg'>

Herein the broken line designates a valence bond. 

Of the acid labile groups represented by R$^{6 }$in formula (1 b ), 65 alkoxymethyl groups having the general formula (le) are most preferred. 

<img src='content_image/911407.jpg'>

Herein the broken line designates a valence bond. Re is a straight, branched or cyclic C$_{1 }$-C$_{15 }$monovalent hydrocarbon group. 

Illustrative examples of the acid labile group having for› mula (le) are given below, but not limited thereto. 

<img src='content_image/911406.jpg'>

