Chemistry of Sulfenic Acids. 5. A Novel Rearrangement of 2,4,6-Trineopentylbenzenesulfenic Acid to 2-tert-Butyl-4,6-dineopentylbenzothiete and 3,3-Dimethyl-4,4-dihydro-6,8-dineopentylbenzothiapyran. Synthesis of Thiete Sulfoxides

Article abstract of DOI:10.1021/jo00166a028

2,4,6-Trineopentylbenzenesulfenic acid (4), prepared by flash vacuum pyrolysis of the corresponding n-butyl sulfoxide, 5, undergoes a novel rearrangement to give benzothiete 7 and benzothiapyran 8.A mechanism involving a 1,4-dehydration of the sulfenic acid to afford an intermediate o-thioquinone methide 6a is proposed.Oxidation of 7 gives the stable benzothiete sulfoxide 10 in good yield, whereas oxidation of thiete 11 gave dimeric sulfoxide 14.The stability of sulfinyl radicals (RSO.) is the proposed reason for the high reactivity of thiete sulfoxides.