Enantioselective total synthesis of a natural hydrocarbazolone alkaloid, identification of its stereochemistry, and revision of its spectroscopic data. Issue 8 (15th August 2017)

• Record Type: Journal Article
• Authors: Wu, Siyuan; Harada, Shinji; Morikawa, Takahiro; Nishida, Atsushi
• Is Part Of: Tetrahedron, asymmetry. Volume 28:Issue 8(2017)
• Page Start: 1083
• Page End: 1088
• Publication Date: 2017-08-15
• Subjects: Asymmetry (Chemistry) -- Periodicals; 547.005
• DOI: 10.1016/j.tetasy.2017.07.005
• Languages: English
• ISSNs: 0957-4166

Abstract

Graphical abstract: Abstract: The natural hydrocarbazolone alkaloid (1 R, 2 R, 3 R )-3-hydroxy-1, 2-dimethyl-1, 2, 3, 9-tetrahydro-4H-carbazol-4-one has been synthesized in a catalytic and enantioselective manner. A key hydrocarbazole derivative was constructed by the holmium-catalyzed Diels-Alder reaction of (silyloxyvinyl)indole as the diene. Total synthesis of the natural product clarified the ambiguity in the spectroscopic data reported for natural products. Abstract : (1 R, 2 R, 3 R )-3-Hydroxy-1, 2-dimethyl-1, 2, 3, 9-tetrahydro-4 H -carbazol-4-one: C14 H15 NO2 [ α ]D 25 = +4.0 ( c 0.6, MeOH) 93% ee Absolute configuration: (1 R, 2 R, 3 R ) Abstract : ((1 R, 2 S, 9a S )-9-((4-Methoxyphenyl)sulfonyl)-2-methyl-4-((triisopropylsilyl)oxy)-2, 3, 9, 9a-tetrahydro-1 H -carbazol-1-yl)methanol: C30 H43 NO5 SSi [ α ]D 25 = +212.5 ( c 0.6, CHCl3 ) 89% ee Absolute configuration: (1 R, 2 S, 9a S ) Abstract : ((1 R, 2 S, 9a S )-9-((4-Methoxyphenyl)sulfonyl)-2-methyl-4-((triisopropylsilyl)oxy)-2, 3, 9, 9a-tetrahydro-1 H -carbazol-1-yl)methyl methanesulfonate: C31 H45 NO7 S2 Si [ α ]D 25 = +190.8 ( c 1.0, CHCl3 ) 94% ee Absolute configuration: (1 R, 2 S, 9a S ) Abstract : (1 R, 2 S, 9a S )-9-((4-Methoxyphenyl)sulfonyl)-1, 2-dimethyl-4-((triisopropylsilyl)oxy)-2, 3, 9, 9a-tetrahydro-1 H -carbazole: C30 H43 N1 O4 SSi [ α ]D 25 = +241.8 ( c 1.0, CHCl3 ) 92% ee Absolute configuration: (1 R, 2 S, 9a S ) Abstract : (1 R, 2 S )-9-((4-Methoxyphenyl)sulfonyl)-1, 2-dimethyl-1, 2, 3, 9-tetrahydro-4 H -carbazol-4-one: C21 H21 NO4 S [ α ]D 25 = +230.6 ( c 1.0, CHCl3 ) 92% ee Absolute configuration: (1 R, 2 S ) Abstract : (1 R, 2 R, 3 R )-3-: Hydroxy-9-((4-methoxyphenyl)sulfonyl)-1, 2-dimethyl-1, 2, 3, 9-tetrahydro-4 H -carbazol-4-one C21 H21 NO5 S [ α ]D 25 = +220.9 ( c 1.0, CHCl3 ) 92% ee Absolute configuration: (1 R, 2 R, 3 R ) Abstract : ((1 R, 2 S, 9a S )-9-((4-Methoxyphenyl)sulfonyl)-4-((triisopropylsilyl)oxy)-2, 3, 9, 9a-tetrahydro-1 H -carbazole-1, 2-diyl)dimethanol: C30 H43 NO6 SSi [ α ]D 25 = +161.2 ( c 0.4, CHCl3 ) Absolute configuration: (1 R, 2 S, 9a S ) Abstract : ((1 R, 2 S, 9a S )-9-((4-Methoxyphenyl)sulfonyl)-4-((triisopropylsilyl)oxy)-2, 3, 9, 9a-tetrahydro-1 H -carbazole-1, 2-diyl)bis(methylene)dimethanesulfonate: C32 H47 NO10 S3 Si [ α ]D 25 = +181.9 ( c 1.0, CHCl3 ) Absolute configuration: (1 R, 2 S, 9a S )