Complete Reversal in Regioselectivity in the Baeyer−Villiger Reaction of an α-CF3-Ketone and Theoretical Rationale for Axial Orientation of Sterically Demanding CF3 Group at the Transition State
摘要:
[GRAPHICS]The regioselectivity of the Baeyer-Villiger reaction of alpha-CF3-ketone is completely reversed from that in alpha-F-eq-ketone. Theoretical study rationalized that the reaction proceeds with the sterically demanding CF3 group in an axial orientation by strong dipole interaction. The guiding principle that strong dipole interaction can overcome steric repulsion as a determining factor not only in regio- but also in stereocontrol is proposed.
Reaction of perfluoroalkyl iodides with silyl enol ethers mediated by Et3B in the presence of a base provides perfluoroalkylated silyl enol ethers. Meanwhile, treatment of germyl enol ethers with perfluoroalkyl iodides affords β-perfluoroalkyl ketones in good yields.
“Pseudo-cationic” trifluoromethylation of enol esters with sodium trifluoromethanesulfinate.
作者:Bernard R. Langlois、Eliane Laurent、Nathalie Roidot
DOI:10.1016/s0040-4039(00)91604-6
日期:1992.3
Enol esters are converted into α-trifluoromethylated enol esters and/or ketones with sodium trifluoromethanesulfinate and t-butyl hydroperoxide in the presence of catalytic amounts of Cu(II).
[reaction: see text] The radical trifluoromethylation of ketonesilylenolethers gave alpha-CF(3) ketones in good yields with wide scope of the ketonic substrates including acyclic ketones and cyclopentanone. The use of dialkylzinc to activate the silylenolethers is the key to the efficient radical trifluoromethylation.
Dialkylzinc-accelerated α-Trifluoromethylation of Carbonyl Compounds Catalyzed by Late-transition-metal Complexes
作者:Yuichi Tomita、Yoshimitsu Itoh、Koichi Mikami
DOI:10.1246/cl.2008.1080
日期:2008.10.5
Trifluoromethylation of ketone silyl enol ethers is found to be significantly accelerated by late-transition-metal catalysts and dialkylzincs to give α-trifluoromethyl ketones in good yields. Addition of dialkylzinc is the key to the high yielding α-trifluoromethylation of carbonyl compounds.
Radical Trifluoromethylation of Titanium Ate Enolate
作者:Yoshimitsu Itoh、Koichi Mikami
DOI:10.1021/ol047565a
日期:2005.2.1
The radical trifluoromethylation of ketone titaniumateenolates gave alpha-CF3 ketones in good yields. The use of excess amount of LDA and Ti(OiPr)4 in the preparation of titaniumateenolates is the key to the efficient radical trifluoromethylation. [reaction: see text]