Palladium-catalysed synthesis of α-diallylated ketosulphides of benzothiazole and their transformation into diallyl thiiranes and trienes
摘要:
alpha-Ketosulphides of benzothiazole 1 react with allylic carbonates in the presence of palladium acetate in dichloromethane under mild conditions affording alpha,alpha-diallylated ketosulphides 2 in high yields. Reduction of 2 with sodium borohydride in isopropanol gives episulphides which in turn can be transformed almost quantitatively into trienes.
Stereoselective synthesis of 1,4-dienes by chelation-controlled reduction of benzothiazole β-oxosulfides
作者:Vincenzo Caló、Angelo Nacci
DOI:10.1016/s0040-4039(98)00622-4
日期:1998.5
Allylated beta-oxosulfides of benzothiazole can replace beta-oxophosphane oxides to provide a stereospecific alkene synthesis. These sulfides, by reduction with sodium borohydride afford predominantly syn beta-hydroxy sulfides. DIBAL reduction in the presence of magnesium bromide improves the syn stereomer formation. Base treatment of these beta-hydroxy sulfides affords (Z)-allyl thiiranes which are converted into (E, Z)-dienes. (C) 1998 Elsevier Science Ltd. All rights reserved.