The Claisen rearrangement of precursors bearing a stereogenic centreadjacent to carbon 1 of the pericyclic nucleus has been investigated in the sulfur series. Dithioesters having a methyl and various alkyl or alkenyls groups on the β-carbon were deprotonated by LDA. The resulting enethiolates were allylated on sulfur to give S-allyl ketenedithioacetals. The thio-Claisen transposition of the latter
THE HIGHLY REGIOSELECTIVE COUPLING REACTION OF ALLYLIC ALCOHOLS WITH LITHIUM ENOLATE OF DITHIOESTERS USING 1-CHLORO-2-METHYL-<i>N</i>,<i>N</i>-TETRAMETHYLENEPROPENYLAMINE
作者:Tamotsu Fujisawa、Kazuto Umezu、Toshio Sato
DOI:10.1246/cl.1985.1453
日期:1985.10.5
1-Chloro-2-methyl-N,N-tetramethylenepropenylamine was found to be a good condensation reagent for the regioselective coupling reaction of allylic alcohols with lithium enolate of dithioesters under mild conditions to afford γ,δ-unsaturated dithioesters, which proceeds by a thio-Claisen rearrangement of S-allylic ketene dithioacetals initially formed.