1, 2, 3, 4-Tetramethyl-5-(trifluoromethyl) cyclopentadienide: a unique ligand with the steric properties of pentamethylcyclopentadienide and the electronic properties of …
PG Gassman, JW Mickelson…
文献索引：Gassman, Paul G.; Mickelson, John W.; Sowa, John R. Journal of the American Chemical Society, 1992 , vol. 114, # 17 p. 6942 - 6944
Treatment of a solution of 3 in diethyl ether at 0 OC with lithium metal resulted in metalation of 3. Addition of ethyl trifluoroacetate to this lithio derivative at-40 OC gave an 82% yield of 4.9 Dehydration of 4 with methanesuifonic acid in methylene chloride at 25 OC resulted in a symmetry-allowed cyclization of the resultant carbation to produce 1 in 82% yield as a mixture of double-bond isomers. 8aJ*. 12
