- Asymmetric transfer hydrogenation of prochiral ketones in aqueous media with new water-soluble chiral vicinal diamine as ligand
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(Matrix presented) An easily accessible water-soluble chiral o-sulfonated 1,2-diphenylethlenediamine 2 and its mono-N-tosylated derivative 3 were synthesized for the first time. The ruthenium-complex-catalyzed reduction of prochiral ketones in aqueous media has been examined by using 3 as ligand and sodium formate as the source of hydrogen. The asymmetric transfer hydrogenation of ω-bromo acetophenones was achieved, in which only formate displacement occurred when formic acid/triethylamine azeotrope was used as the hydrogen donor.
- Ma, Yaping,Liu, Hui,Chen, Li,Cui, Xin,Zhu, Jin,Deng, Jingen
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p. 2103 - 2106
(2007/10/03)
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- Synthesis and catalytic reactivity of D4-symmetric dinorbornabenzene-derived metallotetraarylporphyrins
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The condensation of the resolved C2-symmetric benzaldehyde, 1,2,3,4,5,6,7,8-octahydro-1:4,5: 8-dimethanoanthracene-9-carboxyaldehyde, with pyrrole produced the first chiral tetraarylporphyrin 1 exhibiting D4-symmetry. The resolved benzaldehyde was synthesized in seven steps from p-benzoquinone and cyclopentadiene and included a resolution via diastereomeric ketals. A manganese chloride complex of porphyrin 1 was used as a catalyst for the asymmetric epoxidation of aromatic substituted alkenes in the presence of excess sodium hypochlorite in up to 7,200 turnovers and up to 76% e.e and >90% yield.
- Halterman, Ronald L.,Jan, Shyi-Tai,Nimmons, Heather L.,Standlee, David J.,Khan, Masood A.
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p. 11257 - 11276
(2007/10/03)
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