Electroreductive Defluorination of Trifluoromethyl Ketones and Trifluoroacetic Acid Derivatives.
Difluoroenol silyl ethers 5 and 6, difluoroketene silyl (O,O-, O,S-, and O,N-) acetals 9 and 21, and 2,2-difluoro-2-trimethylsilylacetates 10 were prepared by electroreductive defluorination of trifluoromethyl ketones and trifluoroacetic acid derivatives in an MeCN-TBAB-chlorotrialkylsilane system using a carbon rod as an anode and a lead plate as a cathode. TBAF- or KF-CuI-promoted alpha-alkylation of 10 with electrophiles such as aldehydes, ketones, imine, acylhalides, and alkylhalides provided alpha-alkylated-alpha,alpha-difluoroacetates in good to excellent yields.
Uneyama
Kenji
K
Department of Applied Chemistry, Faculty of Engineering, Okayama University, Okayama 700-8530, Japan.
Mizutani
Go
G
Maeda
Kazushige
K
Kato
Tsuyoshi
T