Quick Access to Diverse Polymerizable Molecules (a Monomer Library) by Catalytic [2 + 2 + 2] Cycloaddition Reactions of Functionalized Alkynes

Abstract

The [2 + 2 + 2] cycloaddition reactions of 1,6-diynes and alkynes with a functional group(s), such as epoxide, oxetane, ester, alcohol, phenol, amine, borate, styrene, and methacrylate, catalyzed by a dipimp/CoCl 2 ·6H 2 O/Zn reagent [dipimp: 2-(2,6-diisopropylphenyl)-iminomethyl-pyridine] yielded a variety of polymerizable molecules (monomers) having a 2,3-dihydro-1 H -indene core structure. Similarly, the [2 + 2 + 2] cycloaddition reactions of 1,6-diynes and nitriles with a functional group(s) catalyzed by a dppe/CoCl 2 ·6H 2 O/Zn reagent [dppe: 1,2-bis(diphenylphosphino)ethane] gave a variety of polymerizable molecules (monomers) with a 6,7-dihydro-5 H -cyclopenta[ c ]pyridine core structure. Among the resulting monomers, 5-phenyl-1,3-dihydrospiro[indene-2,3′-oxetane] prepared from 3,3-di(prop-2-ynyl)oxetane and phenylacetylene was representatively polymerized in the presence of BF 3 catalyst. A cationic random copolymerization of one of 1,3-dihydrospiro[indene-2,3′-oxetane] derivatives with 3-ethyl-3-(phenoxymethyl)oxetane and radical random copolymerization of diethyl 5-(4-vinylphenyl)-1 H -indene-2,2(3 H )-dicarboxylate with styrene have also been demonstrated.