Organoselenium Chemistry. Synthesis of Selenetan-3-ol, 1-Bromo-3-selenocyanatopropan-2-ol and 2-Benzylseleno-Substituted Fumaric and Succinic Acids

Approaches to the synthesis of diselenols have led to isolation of several new organoselenium compounds. Removal of mercury, as HgS, from [1,3-diselenylpropan-2-olato(2-)-Se,Se' ]mercury(II) results in decomposition of the organoselenium fragment to selenetan-3-ol. 1,3-Dibromopropan-2-0l reacts with KSeCN to form 1-bromo-3-selenocyanatopropan-2-0l; the selenoethers 2-(benzyl- se1eno)fumaric acid [(Z)-PhCH2SeC(C02H)=CHC02H] and 2-(benzylse1eno)succinic acid [PhCH2SeCH(C02H)CH2C02H] are formed by base-catalysed reaction of phenylmethaneselenol with acetylenedicarboxylic acid and maleic acid, respectively. The conformations adopted by PhCH2XCH(C02H)CH2C02H (X = S, Se) in acetone have been determined by 1H n.m.r. spectroscopy.