- Asymmetric hydrogenation of β-keto esters
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Enantiomerically pure β-hydroxy esters are prepared by a process in which β-keto esters are reacted with hydrogen in the presence of catalysts of the formula LRuX2where X is halogen, acetate, allyl, methallyl, 2-phenylallyl, perchlorate, trifluoroacetate, tetrafluoroborate, hexafluoroantimonate, hexafluorophosphate, hexafluoroarsenate or trichloroacetate, L is a bidentate phospholane of the formula I ?where B=a bridging link with 1-5 carbon atoms between the two phosphorus atoms, R1=H, C1-C6-alkyl, aryl, alkylaryl or SiR23, R2=alkyl or aryl, m=0 or 1, R3=H or OR4, and R4=R1, with the proviso that if m=1 then R3=H and if m=0 then R3≠ H.
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Page column 7
(2008/06/13)
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- Synthesis of Enantiomerically Pure (2R,5R) Disubstituted Pyrrolidines from D-Mannitol
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Pyrrolidines 1 and 2 are obtained from D-Mannitol, giving good total yields and in an enantiomerically pure form.Some comments and studies regarding pyrrolidine ring closure (key step) are also reported.
- Marzi, M.,Minetti, P.,Misiti, D.
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p. 10127 - 10132
(2007/10/02)
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