Preparation of multisubstituted allenes from allylsilanes.
[reaction: see text] A three-step route of converting allylsilanes to functionalized allenes was developed. Thermal decomposition of 1,1-dibromo-2-(silylmethyl)cyclopropanes, which were quantitatively prepared by treatment of allylsilane derivatives with CHBr3/KO(t)Bu, afforded substituted 2-bromo-1,3-butadienes with elimination of bromosilanes. The Pd-catalyzed reaction of the bromodienes with soft nucleophiles gave the allene derivatives. Previously inaccessible tri- and tetrasubstituted allenes can be prepared by this method as well.
Ogasawara
Masamichi
M
Catalysis Research Center and Graduate School of Pharmaceutical Sciences, Hokkaido University, and SORST, Japan Science and Technology Agency, Kita-ku, Sapporo 001-0021, Japan. ogasawar@cat.hokudai.ac.jp
Ge
Yonghui
Y
Uetake
Koichi
K
Fan
Liyan
L
Takahashi
Tamotsu
T