- A versatile Ru catalyst for the asymmetric transfer hydrogenation of both aromatic and aliphatic sulfinylimines
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A highly efficient Ru catalyst based on an achiral, very simple, and inexpensive amino alcohol ligand (2-amino-2-methylpropan-1-ol) has been developed for the asymmetric transfer hydrogenation (ATH) of chiral N-(tert-butylsulfinyl)imines. This complex is able to catalyze the ATH of both aromatic and the most challenging aliphatic sulfinylimines by using isopropyl alcohol as the hydrogen source. The diastereoselective reduction of aromatic, heteroaromatic, and aliphatic sulfinylketimines, including sterically congested cases, over short reaction times (1-4 h), followed by desulfinylation of the nitrogen atom, affords the corresponding highly enantiomerically enriched (ee up to >99%) α-branched primary amines in excellent yields. The same ligand was equally effective for the synthesis of both (R)- and (S)-amines by using the appropriate absolute configuration in the iminic substrate. DFT mechanistic studies show that the hydrogen-transfer process is stepwise. Moreover, the origin of the diastereoselectivity has been rationalized.
- Pablo, Oscar,Guijarro, David,Kovacs, Gabor,Lledos, Agusti,Ujaque, Gregori,Yus, Miguel
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- Exploiting the divergent reactivity of aryl-palladium intermediates for the rapid assembly of fluorene and phenanthrene derivatives
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They all fall down: The value of domino processes can be greatly enhanced when the possibility exists for one to selectively diverge from a common intermediate. In preliminary studies the dual reactivity of aryl-palladium intermediates is exploited. A div
- Zhao, Ya-Bin,Mariampillai, Brian,Candito, David A.,Laleu, Benoit,Li, Mengzhou,Lautens, Mark
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supporting information; experimental part
p. 1849 - 1852
(2009/08/07)
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