Stable Quinone Methides: Regioselective para-Oxidation of a 2,4-bis[(alkylthio)methyl]phenol and addition reactions to quinonemethides

The 2,4‐bis‐functionalized phenol 1 is dehydrogenated regioselectivity with potassium ferricyanide, affording the corresponding p‐quinonemethide 2. Hydrolysis of 2 affords a mixture of dithioacetal 5a and benzaldehyde 6; 1,6‐addition of thiols to 2 gives the dithioacetals 5 of benzaldehyde 6; reaction of 2 with 2,2′‐azobis(isobutyronitrile) (= 2,2′‐dimethyl‐2,2′‐azobis(propanenitrile)) leads to 9a, 9b, and 10, addition products of the 1‐cyano‐1‐methylethyl radical. The structures of all products are confirmed mainly by 1H‐ and 13C‐NMR spectroscopy, and the mode of their formation is discussed.