Alkyl radicals having (t-butylthio)carbonyl group on β- or γ-position gave β- or γ-thiolactones whereas the homologous radical did not give δ-thiolactone. These reactions involve intramolecular radicalsubstitution on the sulfur atom of thioestergroup. Ethylthioesters have much less reactivity to the same substitution.
Both the alpha-protons and carbons of beta-propiothiolactones exhibit atypical downfield chemical shifts. The alpha-protons of beta-propiothioiactones with no heteroatom at the alpha-position appear at 3.53-5.35 ppm, whereas the alpha-carbons appear at 56.9-86.2 ppm. The major cause of the unexpected deshielding effect was rationalized by assuming a through-space interaction between the occupied orbital of the alpha-carbon and the vacant orbital of sulfur, Copyright (C) 2000 John Wiley & Sons, Ltd.
TADA, MASARU;MATSUMOTO, MITSUHIRO;NAKAMURA, TATSUYA, CHEM. LETT.,(1988) N 2, 199-202