Regioselective reactions of 1-alkylidene-2-oxyallyl cations with furan: control of [4 + 3] cycloaddition, [3 + 2] cycloaddition, and electrophilic substitution.
The ring opening of alkylidenecyclopropanone acetal under acidic conditions produces the 1-alkylidene-2-oxyallyl cation as an intermediate, which reacts with furan to give the [3 + 2] and [4 + 3] cycloadducts as well as an electrophilic substitution product. The product distribution is controlled by the oxy substituents of the cation and by the solvent employed.
Fujita
Morifumi
M
Graduate School of Material Science, Himeji Institute of Technology, University of Hyogo, Kohto, Kamigori, Hyogo 678-1297, Japan. fuji@sci.u-hyogo.ac.jp
Oshima
Makoto
M
Okuno
Sakuro
S
Sugimura
Takashi
T
Okuyama
Tadashi
T