Polyisobutylene-Supported Phosphines as Recyclable and Regenerable Catalysts and Reagents

Phosphines are important as catalysts or reagents in synthesis but must be separated from products after a reaction. This report shows that polyisobutylene (PIB)-bound alkyldiaryl- and triarylphosphines are useful as catalysts in addition and allylic amination reactions or as reagents in aza-Wittig and Mitsunobu reactions. Heptane solutions of such phosphines and their oxidized byproducts can be easily separated from polar solutions of organic products, and PIB-phosphine oxides formed during a reaction can readily be reduced to PIB-phosphines for reuse.