Reductive opening of phenyl substituted thiacycloalkanes: New way for sulphur-containing organolithium compounds

Article abstract of DOI:10.1016/S0040-4020(97)00211-1

The reaction of 2-phenyl substituted four, five and six membered thiacycloalkanes (1, 4 and 7) with lithium and a catalytic amount of DTBB (5 mol %) in THF at -78°C leads to the corresponding sulphur-containing benzylic organolithium compounds (2, 5 and 8), which by reaction with different electrophiles [D₂O, Me₃SiCl, Bu(t)CHO, Me₂CO, Et₂CO, (CH₂)₄CO, CO₂] followed by hydrolysis with water afford the expected functionalised mercaptans (3, 6 and 9) in a regioselective manner. Some reaction products (3, 6) are cyclised under acidic conditions (85% phosphoric acid) to yield the corresponding homologous substituted sulphur-containing saturated heterocycles (10, 11).