7462-67-1Relevant articles and documents
Highly enantioselective epoxidation of olefins by H2O2 catalyzed by a non-heme Fe(ii) catalyst of a chiral tetradentate ligand
Mitra, Mainak,Cusso, Olaf,Bhat, Satish S.,Sun, Mingzhe,Cianfanelli, Marco,Costas, Miquel,Nordlander, Ebbe
supporting information, p. 6123 - 6131 (2019/05/16)
The chiral tetradentate N4-donor ligand, 1-methyl-2-({(S)-2-[(S)-1-(1-methylbenzimidazol-2-yl methyl)pyrrolidin-2-yl]pyrrolidin-1-yl}methyl) benzimidazole (S,S-PDBzL), based on a chiral dipyrrolidine backbone, has been synthesized and its corresponding Fe(ii) complex has been prepared and characterized. The X-ray structure of the complex reveals that the Fe(ii) ion is in a distorted octahedral coordination environment with two cis-oriented coordination sites occupied by (labile) triflate anions. The ability of the iron complex to catalyze asymmetric epoxidation reactions of olefins with H2O2 was investigated, using 2-cyclohexen-1-one, 2-cyclopenten-1-one, cis-β-methylstyrene, isophorone, chalcones and tetralones as substrates. Different carboxylic acids were used as additives to enhance yields and enantioselectivities, and 2-ethylhexanoic acid was found to give the best results. The catalysis results indicate that the Fe(ii) complex is capable of effecting comparatively high enantioselectivities (>80%) in the epoxidation reactions.
Asymmetric epoxidation with H2O2 by manipulating the electronic properties of non-heme iron catalysts
Cusso, Olaf,Garcia-Bosch, Isaac,Ribas, Xavi,Lloret-Fillol, Julio,Costas, Miquel
supporting information, p. 14871 - 14878 (2013/10/22)
A non-heme iron complex that catalyzes highly enantioselective epoxidation of olefins with H2O2 is described. Improvement of enantiomeric excesses is attained by the use of catalytic amounts of carboxylic acid additives. Electronic effects imposed by the ligand on the iron center are shown to synergistically cooperate with catalytic amounts of carboxylic acids in promoting efficient O-O cleavage and creating highly chemo-and enantioselective epoxidizing species which provide a broad range of epoxides in synthetically valuable yields and short reaction times.
Stereoselective synthesis of 3,5-dialkyl-3,5-dihydro-3,5-diphenyl-4H- pyrazol-4-ones
Moiseev, Andrey G.,Neckers, Douglas C.
, p. 2901 - 2905 (2007/10/03)
We report stereoselective five-step syntheses of cis-3-ethyl-3,5-dihydro-3, 5-diphenyl-5-methyl-4H-pyrazol-4-one (cis-1b) and trans-3,5-diethyl-3,5-dihydro- 3,5-diphenyl-4H-pyrazol-4-one (trans-1c). The key synthon was 1,3-diphenylpent-2-en-1-one (5b) synthesized in a new one-pot crossed aldol/dehydration reaction of acetophenone with propiophenone using titanium(IV) chloride/tributylamine, followed by treatment with methanesulfonyl chloride and triethylamine. Georg Thieme Verlag Stuttgart.