Gold-catalyzed synthesis of bicyclo[4.3.0]nonadiene derivatives via tandem 6-endo-dig/Nazarov cyclization of 1,6-allenynes.
Catalytic cyclization of 1,6-allenynes was achieved by AuPPh(3)SbF(6) (5 mol %) in cold CH(2)Cl(2) (0 degrees C, 0.5-4 h) to form bicyclo[4.3.0]nonadiene products; this cyclization proceeded more efficiently for a substrate bearing R = alkyl (yields >70%). We propose a reaction mechanism involving a 6-endo-dig cyclization of Au(I)-pi-alkyne, followed by Nazarov cyclization.
Department of Chemistry, National Tsing-Hua University, Hsinchu, Taiwan, 30043, Republic of China.
Guan-You
GY
Lin
Chun-Yao
CY
Yang
Rai-Shung
RS
Liu