Facile synthesis of cyclic polyphenylenes by consecutive inter- and intramolecular cycloadditions of ortho -, meta -, and para -phenylene-tethered triynes

Consecutive inter- and intramolecular [2+2+2] cycloadditions of various phenylene-tethered triynes were comprehensively studied by using chiral rhodium catalysts. ortho-Phenylene-tethered triynes gave chiral o,o,o,o-tetraphenylenes in high-to-excellent enantiomeric excess as dimers. meta-Phenylene-tethered triynes gave chiral o,m,o,m-tetraphenylenes in moderate enantiomeric excess as dimers along with hexaphenylenes as trimers. This is the first synthesis of cis-o,m,o,m-tetraphenylenes; one structure was ascertained by X-ray crystal structure analysis. para-Phenylene-tethered triynes gave o,p,o,p,o,p- hexaphenylenes as trimers along with the formation of o,p,o,p,o,p,o,p- octaphenylenes as tetramers. 1 Introduction 2 Results and Discussion 2.1 ortho-Phenylene-Tethered Triynes 2.2 Naphthylene-Tethered Triynes 2.3 meta-Phenylene-Tethered Triynes 2.4 para-Phenylene-Tethered Triynes 3 Conclusion.