Unusual transposition of allenic framework in intramolecular cyclization of acetal-tethered (allenylmethyl)silanes.
Treatment of acetal-tethered (allenylmethyl)silanes, which were obtained from the corresponding 3-bromo-5-silyl-1,3-pentadienes by a Pd-catalyzed reaction with an acetal-tethered malonate, with TiCl(4) gave not only vinylcyclohexene derivatives via a standard S(E)2' pathway but also unusual allenylcyclopentane species via cyclization at the delta-position. Deuterium-labeling experiments revealed participation of a 1,2-hydride shift in a carbocation intermediate for the formation of the latter products.
Ogasawara
Masamichi
M
Catalysis Research Center and Graduate School of Life Science, Hokkaido University, Kita-ku, Sapporo 001-0021, Japan. ogasawar@cat.hokudai.ac.jp
Okada
Atsushi
A
Murakami
Hidetoshi
H
Watanabe
Susumu
S
Ge
Yonghui
Y
Takahashi
Tamotsu
T