Volhard-Erdmann Cyclization

J. Volhard, H. Erdmann, Ber. 18, 454 (1885).

Synthesis of alkyl and aryl thiophenes by cyclization of disodium succinate or other 1,4-difunctional compounds (γ-oxo acids, 1,4-diketones, chloroacetyl-substituted esters) with phosphorus heptasulfide:

L. H. Friedburg, J. Am. Chem. Soc. 12, 83 (1890); J. Chem. Soc. 58, 1400 (1890); R. Phillips, Org. Synth. coll. vol. II, 578 (1943); F. F. Blicke, Heterocycl. Compd. 1, 212 (1950); D. E. Wolf, K. Folkers, Org. React. 4, 412 (1951); R. F. Feldkamp, B. F. Tullar, Org. Synth. coll. vol. IV, 671 (1963).