Methanol → (S)-Ethyl 2-(1-phenylethylamino)cyclohex-1-enecarboxylate
Reaction equation
CO.O=[C:4]1[CH2:9][CH2:8][CH2:7][CH2:6][CH:5]1[C:10]([O:12][CH2:13][CH3:14])=[O:11].[C:15]1([C@@H:21]([NH2:23])[CH3:22])[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=1.FC(F)(F)S([O-])(=O)=O.[Yb+3].FC(F)(F)S([O-])(=O)=O.FC(F)(F)S([O-])(=O)=O>CCCCCCC>[C:15]1([C@@H:21]([NH:23][C:4]2[CH2:9][CH2:8][CH2:7][CH2:6][C:5]=2[C:10]([O:12][CH2:13][CH3:14])=[O:11])[CH3:22])[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=1Participants
Procedure
In an additional embodiment, (1S,2S)-2-[(S)-1-phenylethyl amino]cyclohexyl)methanol (11) is produced from a starting material comprising ethyl 2-oxocyclohexane carboxylate (6). This embodiment comprises reacting ethyl 2-oxocyclohexane carboxylate (6) with (S)-(−)-1-phenylethylamine (7) in the presence of a catalyst, ytterbium trifluoromethanesulfonate, and heptane to produce (S)-Ethyl 2-(1-phenylethylamino)cyclohex-1-enecarboxylate (8). The next step is reduction of the amine (8) with sodium acetoxyborohydride in the presence of a acetonitrile produce (1R,2S)-Ethyl 2-((S)-1-phenylethylamino)cyclohexanecarboxylate (9), as illustrated in FIG. 1. The production of the cis-cyclohexane derivative (9) is followed by epimerization of the chiral center adjacent to the ethyl ester functionality using sodium t-butoxide to afford trans-cyclohexane derivative (10) as a major diastereomer. Reduction of the ester functionality in compound (10), using lithium borohydride yields (1S,2S)-2-[(S)-1-phenylethyl amino]cyclohexyl)methanol (11) in good overall yield, which is subsequently purified by chromatography.
Sources & evidence
- ORD record
- ord-73cc6ecf57da4efd9f7737e4962d3c2f
- Source dataset
- uspto-grants-2012_10
- Patent number
- US08288565B2
Reaction notes
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