‘Cascade’ radical reactions in synthesis: Condensed thiophenes from ketenethioacetals

(Bu3Sn)2–TBAF: a new combination reagent for the reduction and deuteration of aryl bromides and iodides

The combination of (Bu(3)Sn)(2) and TBAF has been shown to reduce aromatic bromides and iodides in excellent yields under mild conditions. When the residual water in TBAF is exchanged for D(2)O, the halogen is replaced by a deuterium atom.

Preparation of New Nitrogen-Bridged Heterocycles. 55. Reinvestigation of the Bromination/Dehydrobromination of Ethyl 3-[2-(Methylthio)indolizin-3-yl]acrylate Derivatives

The bromination/dehydrobromination reactions of ethyl 3-[1-alkoxycarbonyl-2-(methylthio)indolizin-3-yl]acrylates were reinvestigated. Reactions of the title compounds with two equivalents of bromine, followed by heating of the resulting reaction mixture and then treatment with a base gave the unexpected dialkyl 7-bromothieno[2,3-b]indolizine-2,9-dicarboxylates, while similar reactions using benzyltrimethylammonium tribromide as a brominating agent afforded only non-brominated thieno[2,3-b]indolizine derivatives, which were converted to the corresponding 7-bromo derivatives upon further treatment with bromine.