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
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.