The Barbier‐type allylation of aldehydes and ketones can be carried out with both unsubstituted and γ‐substituted allyl bromides using only a catalytic amount (0.1 equiv.) of In metal in [bmim][Br].
Electrochemical allylation of aldehydes in a solvent-free cavity cell with a graphite powder cathode
作者:Ronny F. M. de Souza、Madalena C. C. Areias、Lothar W. Bieber、Marcelo Navarro
DOI:10.1039/c0gc00947d
日期:——
Mixtures of carbonyl compounds and allyl halides, adsorbed on a graphite powder cathode, were reduced under aqueous anolyte to give high yields of homoallylic alcohols. Catalytic amounts of silver or tetrabutylammonium tetrafluoroborate improved the yields significantly. Inexpensive allyl chloride gave superior results when compared to allyl bromide.
Addition of Halocarboxylic Acids Esters and Halohydrocarbons to Pentafluorobenzaldehyde Promoted by Iron Pentacarbonyl
作者:A. B. Terent'ev、T. T. Vasil'eva、O. V. Chakhovskaya、N. E. Mysova、K. A. Kochetkov
DOI:10.1007/s11178-006-0007-y
日期:2005.11
Iron pentacarbonyl is an efficient promoter of addition to the carbonyl group of pentafluorobenzene of alkyl α-halocarboxylates and alkyl halides. The electron-acceptor character of the pentafluorophenyl group essentially affects the course of reaction and the nature of the arising products.
1-Arylbut-3-en-1-ols react with trimethyl orthoformate in the presence of Lewis acids like InCl 3 , BiCl 3 , TiCl 4 , or BF 3 ·OEt 2 providing homoallyl ethers or homoallyl chlorides in high yields.
The room-temperature ionic liquid (RTIL) [bmim][Br] has been found to be an excellent green and inexpensive medium for the Ga-mediated allylation of aromatic and aliphatic aldehydes and ketones. The RTIL activated the metal via formation of a Ga-N-heterocyclic carbene complex that assisted in the completion of the reaction at ambient temperature with only 0.5 equiv of Ga and 1.2 equiv of allyl bromide with respect to the carbonyl substrates. The present protocol required a much shorter time than those reported in the literature using other metals and solvents and proceeded with good yields and excellent selectivity.