phenol as a directing group, high regioselectivity, good substrate scope, mild reaction conditions, and high efficiency. To the best of our knowledge, this is the first example of a regioselective C−H alkenylation of unprotected phenols utilizing phenolic hydroxyl group as a directing group. The alkenylation of unprotected tyrosine and intramolecular cyclization are also successfully carried out under
Solvent- and Wavelength-Dependence of the Photocleavage of the Cyclobutane Ring in<i>N</i>,<i>N</i>′-Dibutyl-<i>c</i>-3,<i>c</i>-4-bis(2-hydroxyphenyl)-<i>r</i>-1,<i>c</i>-2-cyclobutanedicarboxamide
The ratio between two photocleavage directions of the cyclobutanering in the title compound varies with the solvent polarity and the irradiation wavelength, and the effect of the solvent polarity appears much larger in protic solvents than aprotic ones.