The reactions of Wittig reagents with episulfides gave symmetrical olefins and triphenylphosphine sulfide in moderate yields. The same olefins were obtained by reactions of Wittig reagents with elemental sulfur. These reactions might proceed through thiocarbonyl intermediates, the existence of which was confirmed by Diels–Alder reactions with dienes.
3,6‐Dihydro‐2H‐thiopyrans are important structural motifs both in organic synthesis and medicinal chemistry. A continuous flow‐process for the photochemical generation of thioaldehydes from phenacyl sulfides and the ensuing [4+2]‐cycloaddition with electron‐rich 1,3‐dienes was developed. The cycloadducts were obtained with excellent yields in short reaction times and much improved productivities as
Synthesis and thermal transformation of stable monocyclic λ4-thiabenzenes
作者:Hiroshi Shimizu、Noriaki Kudo、Tadashi Kataoka、Mikio Hori
DOI:10.1039/b102806p
日期:——
The stable monocyclic λ4-thiabenzenes 6aâe, which are stabilized with electron-withdrawing substituents such as benzoyl, cyano and alkoxycarbonyl groups, are synthesized in high yields by proton abstraction from the corresponding thiopyranium salts 5aâe with triethylamine in ethanol. The ylidic properties of the λ4-thiabenzenes are established based on spectral and chemical evidence. Thermal decomposition of the λ4-thiabenzenes affords alkyl-rearranged products 7, 8, and 9, thienofuran derivatives 10 (from benzoyl-substituted λ4-thiabenzenes), and thiophene derivatives 11. A plausible mechanism for the formation of those products is also discussed.
Generation of thioaldehydes from sodium thiosulphate S-esters (Bunte salts)
作者:Gordon W. Kirby、Alistair W. Lochead、Gary N. Sheldrake
DOI:10.1039/c39840000922
日期:——
Treatment of Buntesalts, ZCH2SSO3Na where Z is an electron-withdrawing group, with triethylamine and calcium chloride in the presence of cyclopentadiene or 2,3-dimethylbuta-1,3-diene gives the corresponding cycloadducts of the transient thioaldehydes, ZCHS; the cyclopentadiene adducts dissociate upon heating thereby allowing transfer of the thioldehydes to dimethylbutadiene.