American Chemical Society
jo6b03035_si_001.pdf (6.89 MB)

CAr–O Rotamers in 3,3′-Disubstituted BINOL Esters

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journal contribution
posted on 2017-02-22, 00:00 authored by Takeo Sakai, Junpei Matsuoka, Masayuki Shintai, Yuji Mori
Rotamers around the CAr–O bond were disclosed in 3,3′-disubstituted BINOL esters by NMR spectroscopy. A bulky R1 group increased the rotational barrier. The pivalate showed two rotamers at 2 °C, and broad signals were observed close to room temperature when R2 = Ph. The highest rotational barrier was recorded for the (tetra­cyano­cyclo­penta­dienyl)­carboxylate, and C–O rotamers were present at room temperature. DFT calculations indicated the presence of repulsion between R1 and R2 during rotation of the CAr–O bond.