NEW MATERIAL:The compound of formula I (R1 is methyl, ethyl or methoxyethyl; R2 is H or methyl).

EXAMPLE: (Norbornenylmethyl) triethoxysilane.

USE: A surface-treating agent for reinforcing material such as glass fiber or a silane coupling agent.

PREPARATION: An allyl or 2-butenyl trialkoxysilane of formula II is made to react with cyclopentadiene or dicyclopentadiene usually in an inert atmosphere in an autoclave preferably at 100-140°C for 1-4hr.