Silanol: A Traceless Directing Group for Pd-Catalyzed o-Alkenylation of Phenols
C-H activation of phenols using a silanol directing group.
Nice paper by Gevorgyan et al. (University of Illinois, Chicago, USA) about C-H functionalization. In this case, they tackle not the usual N-containing heterocycle, but phenols. The trick is done by means of a directing group, di-tert-butylsilanol, which is removed in a semi-one-pot procedure after the functionalization of the ortho position. More than 20 examples are described, exploring both the phenol (no ortho examples, just in case, haha) and the alkene (acrylates, acrolein, alkyl vinyl ketones, diethyl maleate, etc.).
J. Am. Chem. Soc., 2011, 133 (32), pp 12406–12409. See: 10.1021/ja204924j