Reactions
(S)-b-AMino-4-Methoxy-benzeneethanol could synthize oxidatively
cleavable chiral auxiliary-bearing tetramate derivative 1-[(S)-2-Hydroxy-1-(4-methoxyphenyl)ethyl]-4-methoxy-3-methyl-1H-pyrrol2(5H)-one with (E)-4-bromo-3-methoxy-2-methyl-2-butenoate. Due to its chirality, it can also be used to synthesize various chiral organics, such as 1-[(S) -2-hydroxy-1 -(4-methoxyphenyl)ethyl] -4-methoxy-3-methyl-1h-Pyrrol2 (5H)-one[1-2].
Synthesis
1.To an ice-cooled mixture of lithium borohydride (16.5 g, 759 mmol) in THF (270 mL) was added trimethylsilyl chloride (194 mL, 1.52 mol).
2.After stirring for 30 minutes, a mixture of (2S)-2-amino-2-(4-methoxyphenyl)acetic acid (45.9 g, 253 mmol) in THF (1.00 L) was added dropwise to the reaction.
3.Then the reaction mixture was stirred at rt overnight.
4.The reaction was quenched with MeOH, and the resulting mixture was concentrated in vacuo.The residue was diluted with 1M sodium hydroxide aq.solution and chloroform, and filtered through a pad of Celite.
5.The filtrate was diluted with brine, and organic layer was separated. The aqueous layer was extracted with chloroform. The combined organic extracts were dried over sodium sulfate, filtered, and concentrated in vacuo to give (S)-b-AMino-4-Methoxy-benzeneethanol (37.1 g) as red solids.
References
[1] Lan H, et al. The first enantioselective synthesis of cytotoxic marine natural product palau’imide and assignment of its C-20 stereochemistry. Chemical Communications, 2010; 46: 5319-532.
[2] Shemet A, et al. Total Synthesis of (?)-Rhazinilam and Formal Synthesis of (+)-Eburenine and (+)-Aspidospermidine: Asymmetric Cu-Catalyzed Propargylic Substitution. Organic Letters, 2017; 19: 5529–5532.
