Clayden, Jonathan and Moran, Wesley J. (2007) Synthesis of densely functionalised arenes using [2 + 2 + 2] cycloaddition reactions. Organic & Biomolecular Chemistry, 5 (7). p. 1028. ISSN 14770520

Rh(I)–catalysed [2 + 2 + 2] cycloaddition allows the synthesis of aryl ethers and diaryl methanes containing a high degree of steric hindrance from relatively simple diyne and alkyne precursors. The diarylmethanes made in this way show no evidence in their NMR spectra, however, of rotational restriction.