- Stereoselective α-amidoalkylation reactions of phenylglycinol-derived bicyclic lactams
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The stereochemical outcome of α-amidoalkylation reactions from the chiral non-racemic bicyclic lactams trans-1 and cis-1 using indole, allyltrimethylsilane, higher order organocuprates, TMSCN, and Grignard reagents is discussed.
- Amat, Mercedes,Escolano, Carmen,Llor, Nuria,Huguet, Marta,Perez, Maria,Bosch, Joan
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p. 1679 - 1683
(2007/10/03)
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- Enantioselective synthesis of piperidine, indolizidine, and quinolizidine alkaloids from a phenylglycinol-derived δ-lactam
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Starting from a common lactam, (3R,8aS)-5-oxo-3-phenyl-2,3,6,7,8,8a-hexahydro-5H-oxazolo[3,2-a]pyridine (1), or its enantiomer, the enantioselective synthesis of 2-alkylpiperidines and cis- and trans-2,6-dialkylpiperidines is reported. The potential of this approach is illustrated by the synthesis of the piperidine alkaloids (R)-coniine, (2R,6S)-dihydropinidine, (2R,6R)-lupetidine, and (2R,6R)-solenopsin A, the indolizidine alkaloids (5R,8aR)-indolizidine 167B and (3R,5S,8aS)-monomorine I, and the nonnatural base (4R,9aS)-4-methylquinolizidine.
- Amat, Mercedes,Llor, Nuria,Hidalgo, Jose,Escolano, Carmen,Bosch, Joan
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p. 1919 - 1928
(2007/10/03)
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- Asymmetric synthesis of (+) and (-) trans-2,6-dimethylpiperidines
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(+) aid (-) trans-2,6-dimethylpiperidines 9 have been prepared from diastereomeric lactams 6 and 11, both available from (R)-(-)-phenylglycinol 4. Diastereoselective C-2 alkylation afforded oxazolidines 7 and 12. Reduction of 7 with LiAlH4 or NaBH4 led to trans-2,6-8 with total retention of configuration. When 12 was reduced with NaBH4, trans derivative 13a was isolated as the major isomer. A mechanism is proposed to explain the different results.
- Freville, Stephanie,Bonin, Martine,Celerier, Jean-Peirre,Husson, Henri-Philippe,Lhommet, Gerard,Quirion, Jean-Charles,Thuy, Vu Moc
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p. 8447 - 8456
(2007/10/03)
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- Synthesis of enantiopure piperidines. Total synthesis of (2R,6S)-2-methyl-6-propylpiperidine [(-)-dihydropinidine]
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Enantiomerically pure 2-alkyl-, 3-alkyl-, 4-alkyl-, and cis-2,6-dialkylpiperidines are prepared from the chiral, non-racemic oxazolopiperidone 1. An asymmetric synthesis of (2R,6S)-(-)-dihydropinidine is reported.
- Amat, Mercedes,Llor, Nuria,Hidalgo, Jose,Hernandez, Albert,Bosch, Joan
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p. 977 - 980
(2007/10/03)
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