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The Hancock Alkaloids (-)-Cuspareine, (-)-Galipinine, (-)-Galipeine, and (-)-Angustureine: Asymmetric Syntheses and Corrected 1H and 13C NMR Data
被引:30
作者:
Davies, Stephen G.
[1
]
Fletcher, Ai M.
[1
]
Houlsby, Ian T. T.
[1
]
Roberts, Paul M.
[1
]
Thomson, James E.
[1
]
Zimmer, David
[1
]
机构:
[1] Univ Oxford, Chem Res Lab, Dept Chem, Mansfield Rd, Oxford OX1 3TA, England
来源:
JOURNAL OF NATURAL PRODUCTS
|
2018年
/
81卷
/
12期
关键词:
ENANTIOSELECTIVE TOTAL-SYNTHESIS;
STEREOSELECTIVE-SYNTHESIS;
ABSOLUTE-CONFIGURATION;
CONJUGATE ADDITION;
TETRAHYDROQUINOLINES;
DERIVATIVES;
ACID;
HYDROGENATION;
QUINOLINES;
KETONES;
D O I:
10.1021/acs.jnatprod.8b00672
中图分类号:
Q94 [植物学];
学科分类号:
071001 ;
摘要:
The asymmetric syntheses of all members of the Hancock alkaloid family based upon a 2-substituted N-methyl-1,2,3,4-tetrahydroquinoline core are delineated. The conjugate addition of enantiopure lithium N-benzyl-N-(alpha-methyl-p-methoxybenzyl)amide to 5-(o-bromophenyl)-N-methoxy-N-methylpent-2-enamide is used to generate the requisite C-2 stereogenic center of the targets, while an intramolecular Buchwald-Hartwig coupling is used to form the 1,2,3,4-tetrahydroquinoline ring. Late-stage diversification completes construction of the C-2 side chains. Thus, (-)-cuspareine, (-)-galipinine, (-)-galipeine, and (-)-angustureine were prepared in overall yields of 30%, 28%, 15%, and 39%, respectively, in nine steps from commercially available 3-(o-bromophenyl)propanoic acid in all cases. Unambiguously corrected H-1 and C-13 NMR data for the originally isolated samples of (-)-cuspareine, (-)-galipinine, and (-)-angustureine are also reported, representing a valuable reference resource for these popular synthetic targets.
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页码:2731 / 2742
页数:12
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