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-quinonemet hide 2. Hydrolysis of 2 affords a mixture of dithioacetal 5a and benza ldehyde 6; 1,6-addition of thiols to 2 gives the dithioacetals 5 of be nzaldehyde 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 H-1- and C-13-NMR spectroscopy, and t he mode of their formation is discussed.