Remarkably Slow Rotation about a Single Bond between an sp(3)-Hybridised Carbon Atom and an Aromatic Ring without ortho Substituents

Sarah Murrison, David Glowacki, Christian Einzinger, James Titchmarsh, Stephen Bartlett, Ben McKeever-Abbas, Stuart Warriner, Adam Neson

Research output: Contribution to journalArticle (Academic Journal)peer-review

13 Citations (Scopus)


A series of polycycles was prepared by using a three-component Joullie-Ugi reaction. The rate of rotation about the bond between a highly hindered bridgehead and a phenyl ring with no ortho substituents was measured by using, in general, variable-temperature HPLC. The rate of rotation was highly dependent on substitution and rotamer half-lives of up to 21 h at 298 K were observed. Insights into the effect of substitution on the rate of rotation were gleaned through electronic structure calculations on closely related derivatives. Rotamers resulting from restricted rotation about a bond between an sp(3)-hybridised carbon atom and a phenyl ring with no ortho substituents were isolated for the first time, and the equilibration of the separated rotamers was followed by using analytical HPLC. It was demonstrated, for the first time, that a highly hindered environment for the sp(3)-hybridised atom is sufficient for slow bond rotation about a single bond between sp(3)- and sp(2)-hybridised carbon atoms.

Original languageEnglish
Pages (from-to)2185-2189
Number of pages5
JournalChemistry - A European Journal
Issue number9
Publication statusPublished - 2009

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