Discovery of a new case of a Winstein/Roberts non-classical cation

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Houk Kendall 2018 small

Houk team joins Nobelist Feringa and Wolf Prize Laureate Fujita to discover a Winstein/Roberts non-classical cation in an unexpected place.

The latest issue of the Journal of the American Chemical Society features a paper by Professor Kendall Houk’s group (Pier Alexandre Champagne, postdoc now in Ottawa), the Ben Feringa group in Netherlands (Feringa was 2016 Nobelist for molecular machines with former UCLA faculty member Fraser Stoddart), and the Makoto Fujita group in Japan (Fujita and former UCLA faculty member Omar Yaghi just won the Wolf Prize).  

JACS 2018 Group

The team – Pier Alexandre Champagne, Makoto Fujita, Kendall Houk, and Ben Feringa

They found that an unexpected stereospecific rearrangement involves a transition state that is a non-classical bicyclobutonium ion pair, and this species can be formed faster as an intermediate with ZnBr2 present. The bicyclobutonium ion structure, now easily calculated, was first postulated by John D. “Jack” Roberts (UCLA alum for whom a term chair was recently created at UCLA) and became one of the celebrated non-classical cations made known to the world by UCLA’s Saul Winstein. Houk holds the Saul Winstein Chair in Organic Chemistry at UCLA.

JACS 2018 Image

A bicyclobutonium transition state connects two enantiomeric cyclopropylcarbinyl.