The Preparation of Thiophenes and Tetrahydrothiophenes

Wolf, Donald E.; Folkers, Karl


Thiophenes and tetrahydrothiophenes are discussed as separate major divisions in this chapter because there are significant differences in the general methods by which these two similar types of compounds are prepared. The general reactions that lead to the formation of thiophenes may be segregated in the following five general classifications (1) Reaction of the 1,4-difunctional compounds with sulfides; (2) reaction of unsaturated compounds with sulfides; (3) reaction of 1,2-difunctional compounds with thiodiacetic acid and esters; (4) reaction of aryl methyl ketones with sulfides; (5) miscellaneous cyclization reactions. Similarly the reactions that form tetrahydrothiophenes may be grouped into four general classifications: (1) Reaction of 1,4-difunctional compounds with sulfides; (2) Dieckmann cyclization; (3) Catalytic method; (4) miscellaneous methods. All of the above are discussed in this chapter.