Au(PPh3)Cl–AgSbF6-catalyzed rearrangement of propargylic 1,3-dithianes: formation of 8-membered 1,3-bisthio-substituted cyclic allenesw
نویسندگان
چکیده
Au-catalyzed rearrangement of alkynes has attracted considerable attention in recent years. In particular, the Au-catalyzed rearrangement of propargyl acetate generates Au–carbene species through 1,2-acetoxy migration. The Au–carbene species thus generated undergoes a variety of transformations. Moreover, Au-catalyzed rearrangement of propargyl acetate to allene through 1,3-shift of the acetoxy group has recently been reported. We have focused our attention on Au-catalyzed reaction of propargylic sulfides and dithioacetals. These sulfur-containing substrates are converted into indene derivatives upon catalysis by the Au-complex, presumably through 1,2-sulfur migration and generation of a Au–carbene species (eqn (1)). As a continuation, we further studied the Au-catalyzed reaction of propargylic 1,3-dithianes. To our surprise, 1,3-bisthio-substituted cyclic allenes are isolated as the major product. The thio-substituted eight-membered allene thus obtained is stable and the structure has been fully characterized by spectra data and X-ray crystallographic analysis. Here we communicate the results of this investigation.
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