Hydroxyl-yne click reaction for facile modification of commercial polyvinyl butyral

Abstract

Hydroxyl-yne click reaction, the reaction between mainly primary or secondary alcohols and electron-deficient alkynes in the presence of a catalytic amount of base, fulfills many requirements of “click” reactions, such as high efficiency, stereoselectivity, and mild reaction conditions. The reaction has proven to be useful for both small organic molecules and has then gained much popularity in polymer synthesis. In this study, we aimed to investigate the efficiency of hydroxyl-yne click reaction for post-polymerization modification (PPM) of commercial polymers possessing alcohol functionality. Polyvinyl butyral with some degree of free OH units was chosen as the polymer platform and modified with various propiolate esters in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) as the organobase at room temperature in only 5 min, affording vinyl ether pendant polymers only in <i>E</i>-configuration. The modified polymers were obtained in high to quantitative efficiencies and high yields, and their chemical structures were confirmed by several spectroscopic analyses. We believe the presented strategy will extend our knowledge of X-yne click reactions and emerge as a powerful tool for the PPM method.