34298-75-4Relevant articles and documents
Reactions of 2,2-dialkylvinyl iodonium salt with halide ions
Okuyama, Tadashi,Sato, Koichi,Ochiai, Masahito
, p. 2341 - 2349 (2000)
Reactions of (E)- and (Z)-2-methyl-5-phenyl-1-pentenyl(phenyl)iodonium (1) salts with halide ions were examined in various solvents at 50 or 60°C. The main products are those of substitution, 1-halo-2-methyl-5-phenyl-1-pentenes, mainly of inversion but involving some retained products. Varying amounts of rearranged products are also formed. Reaction follows pseudo-first-order kinetics at [1] a pre-equilibrium formation of the adduct, λ 3-haloiodane, and first-, second-, and third-order reaction pathways. The first-order rate constant for the E isomer, (E)-1, is greater than that for (Z)-1, while the opposite is the case for the second- and third-order terms. The main reaction is considered to proceed via a vinylic in-plane S(N)2 mechanism to lead to inversion while some retention routes via out-of-plane S(N)2 and/or ligand coupling mechanism are also possible. Competing rearrangement reactions occur by the β-alkyl participation and no evidence for formation of the primary vinylic cation was obtained.
Regioselective Rhodium-Catalyzed Addition of β-Keto Esters, β-Keto Amides, and 1,3-Diketones to Internal Alkynes
Beck, Thorsten M.,Breit, Bernhard
supporting information, p. 5839 - 5844 (2016/12/18)
The first rhodium-catalyzed regioselective addition of 1,3-dicarbonyl compounds, including β-keto esters, β-keto amides, and 1,3-diketones, to internal alkynes furnishes branched allylic compounds. By applying RhI/DPEphos/TFA as the catalytic system, aliphatic as well as aromatic internal methyl-substituted alkynes act as suitable substrates to yield valuable branched α-allylated 1,3-dicarbonyl compounds regioselectively in good to excellent yields. A simple basic saponification–decarboxylation procedure provides access to valuable γ,δ-unsaturated ketones. The reaction shows a broad functional-group tolerance, and numerous structural variations on both reaction partners highlight the synthetic potential and flexibility of this method.
Decarboxylative elimination of enol triflates as a general synthesis of acetylenes.
Fleming, Ian,Ramarao, Chandrashekar
, p. 1504 - 1510 (2007/10/03)
The enol trifluoromethanesulfonates 4, 8, 12, 17 and 20 of tert-butyl beta-ketodiesters and beta-ketoesters can be hydrolysed to the corresponding carboxylic acids by dissolution in trifluoroacetic acid. The dicarboxylic acids undergo mild decarboxylative elimination to give the acetylenic acids 4 and 9 in aqueous sodium bicarbonate solution at room temperature. Similarly, the monocarboxylic acids give the terminal and mid-chain acetylenes 13, 18, 21, and 24 by refluxing in acetone with potassium carbonate. One of the substituents on the acetylenes can be methyl, primary alkyl, secondary alkyl or ethynyl, and the other can be a carboxylic acid, hydrogen or primary alkyl, but the enol trifluoromethanesulfonates could not be prepared when one of the substituents was tert-butyl, nor when both substituents on the precursor to the acetylene were secondary alkyl.
