40596-16-5Relevant articles and documents
Iridium-Catalyzed coupling reaction of primary alcohols with 2-alkynes leading to hydroacylation products
Hatanaka, Shintaro,Obora, Yasushi,Ishii, Yasutaka
experimental part, p. 1883 - 1888 (2010/06/20)
A novel iridium-catalyzed intermolecular coupling reaction of primary alcohols or aldehydes with 2-alkynes was successfully achieved with high regioselectivity to give hydroacylation products such as α,β- unsaturated ketones in good yields. The mechanistic investigation of the reaction strongly indicated that the coupling proceeds through the initial formation of homoallylic alcohols followed by dehydrogenation to β,γ-unsatutated ketones and then isomerisation, which leads to the hydroacylation products.
Diethylzinc-mediated allylation of carbonyl compounds catalyzed by [(NHC)(PR3)PdX2] and [(NHC)Pd(η3-allyl)Cl] complexes
Flahaut, Alexandre,Toutah, Krimo,Mangeney, Pierre,Roland, Sylvain
experimental part, p. 5422 - 5432 (2010/06/15)
[(NHC)(PR3)PdX2] complexes (NHC = N-heterocyclic carbene) are active precatalysts in the palladium-catalyzed allylation of carbonyl compounds with allylic acetates and diethylzinc. A comparative study examining the catalytic activity of a series of six of these complexes was carried out with allyl and cinnamyl acetates. [(IMeSMe)(PPh3)PdI 2] was found to be the most versatile precatalyst (IMesMe = 1-mesityl-3-methylimidazol-2-ylidene) and the scope of the reaction was investigated with this complex. [(IMeSMe)(PPh3)-PdI2] catalyzes the allylation of aromatic (except 4-nitrobenz-aldehyde) and aliphatic aldehydes (including enolizable aldehydes) with cinnamyl acetate to give the corresponding homoallylic alcohols in 57-98 % yields and dlastereoselectivities ranging from 70:30 to 92:8. The allylation of acetone also takes place under the same conditions, leading to the expected adduct in 63 % yield. The reaction with cyclohexenyl acetate proceeds at room temperature to afford the homoallylic alcohols in 40-78% yields with excellent diastereoselec-tivities (>98:2), but is limited to aromatic aldehydes. An experimental study concerning the mechanism, of the transformation was also carried out. We first demonstrated that the phosphane ligand was not essential for the reaction to take place. [(NHC)Pd(allyl)Cl] complexes are active precatalysts and lead to similar yields in the presence or in the absence of PPh3. Transmetalation of [(NHC)Pd(allyl)Cl] complexes with diethyl- or dimethylzinc, which is a determining step for the mechanism, was studied by 1H NMR spectroscopy. The reaction of [(IPr)Pd(allyl)Cl] with dimethylzinc affords rapidly [(IPr)Pd(η3-allyl)(Me)] but no detectable trace of allylzinc species [IPr = 1, 3-bis(2, 6-diisopropylphenyl)imidazol-2-ylidene]. [(IPr)Pd(η3-allyl)(Me)] was found to be a nucleophilic species able to react smoothly at room temperature with an aldehyde in the absence of zinc to form the corresponding homoallylic alcohol.
Reaction of α-halo organoindium reagents with carbonyl compounds and electron-deficient alkenes
Araki, Shuki,Hirashita, Tsunehisa,Shimizu, Ken,Ikeda, Takahiro,Butsugan, Yasuo
, p. 2803 - 2816 (2007/10/03)
A variety of α-halo organoindium reagents were prepared in situ from the reaction of gem-dihalo compounds with indium metal, and their reactions with carbonyl compounds and electron-deficient alkenes were examined. The reactions of simple 1,1-diiodoalkanes with indium metal gave no defined products but benzal iodide gave stilbene in a moderate yield. α-Halo organoindium reagents derived from α,α-dibromo carbonyl compounds gave oxiranes and cyclopropanes upon the reactions with aldehydes and alkenes, respectively. 3,3-Dichloropropenes reacted with aldehydes in the presence of indium metal to give the corresponding chlorohydrins and/or homoallylalcohols, depending on the structures of both the dichloropropenes and aldehydes employed.
