- Catalytically Asymmetric Pd/Norbornene Catalysis: Enantioselective Synthesis of (+)-Rhazinal, (+)-Rhazinilam, and (+)-Kopsiyunnanine C1-3
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A catalytically asymmetric palladium/norbornene-catalyzed reaction is reported, where α-aryl tetrahydroquinoline derived phosphoramidite L15 is found to be the optimum ligand. Taking advantage of this transformation, the concise and unified enantioselective syntheses of (+)-rhazinal, (+)-rhazinilam, and (+)-kopsiyunnanine C1, C2, and C3 are realized.
- Zhao, Kun,Xu, Shibo,Pan, Chongqing,Sui, Xianwei,Gu, Zhenhua
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supporting information
p. 3782 - 3785
(2016/08/16)
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- Enantioselective Total Syntheses of (-)-Rhazinilam, (-)-Leucomidine B, and (+)-Leuconodine F
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A divergent total synthesis of three structurally distinct natural products from imine 9 was accomplished through an approach featuring: 1) a Pd-catalyzed decarboxylative cross-coupling, and 2) heteroannulation of 9 with bromoacetaldehyde and oxalyl chloride to give tetrahydroindolizine 6 and dioxopyrrole 7, respectively. The former was converted into (-)-rhazinilam, while the latter was converted into (-)-leucomidine B and (+)-leuconodine F. A substrate-directed highly diastereoselective reduction of a sterically unbiased double bond by using a homogeneous palladium catalyst was developed. A self-induced diastereomeric anisochronism (SIDA) phenomenon was observed for leucomidine B. Be divergent: Concise total syntheses of (-)-rhazinilam, (-)-leucomidine B, and (+)-leuconodine F were accomplished from the common intermediate A. A homogeneous palladium catalyst was exploited for the first time to accomplish a substrate-directed highly diastereoselective hydrogenation of a sterically unbiased double bond. A self-induced diastereomeric anisochronism (SIDA) phenomenon was observed for leucomidine B.
- Dagoneau, Dylan,Xu, Zhengren,Wang, Qian,Zhu, Jieping
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p. 760 - 763
(2016/02/27)
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- Solvent-controlled switchable C-H alkenylation of 4-aryl-1H-pyrrole-3-carboxylates: Application to the total synthesis of (±)-rhazinilam
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A solvent-controlled switchable C-H alkenylation of 4-aryl-1H-pyrrole-3-carboxylates via a Pd(OAc)2 catalyzed oxidative Heck reaction was first realized. The corresponding C2 and C5 alkenylation products were obtained in good yields with high regioselectivities, respectively. The selective C5-alkenylation was successfully applied to the total synthesis of (±)-rhazinilam.
- Su, Youla,Zhou, Haipin,Chen, Jiaxuan,Xu, Jinyi,Wu, Xiaoming,Lin, Aijun,Yao, Hequan
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p. 4884 - 4887
(2015/04/27)
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- Biosynthetically inspired divergent approach to monoterpene indole alkaloids: Total synthesis of mersicarpine, leuconodines b and d, leuconoxine, melodinine e, leuconolam, and rhazinilam
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Inspired by their potential biosynthesis, we have developed divergent total syntheses of seven monoterpene indole alkaloids including mersicarpine, leuconodines B and D, leuconoxine, melodinine E, leuconolam, and rhazinilam, and one unnatural analogue with an unprecedented structural skeleton. The key steps involve a Witkop-Winterfeldt oxidative indole cleavage followed by transannular cyclization. The transannular cyclization product was then converted to the corresponding structural skeletons by pairing its functional groups into different reaction modes.
- Yang, Yang,Bai, Yu,Sun, Siyuan,Dai, Mingji
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p. 6216 - 6219
(2015/02/19)
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- Chemical synthesis of aspidosperma alkaloids inspired by the reverse of the biosynthesis of the rhazinilam family of natural products
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Pyrrole reduction: Iterative metal-catalyzed C-H functionalization reactions facilitated the preparation of a highly substituted pyrrole derivative. This derivative could be transformed into the pyrrole-containing secondary metabolite, rhazinilam, which could in turn be transformed through a reductive transannular cascade process into the structurally complex pyrrolidine-containing alkaloid natural product, aspidospermidine.
- McMurray, Lindsay,Beck, Elizabeth M.,Gaunt, Matthew J.
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p. 9288 - 9291
(2012/10/30)
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- Total synthesis of rhazinilam: Axial to point chirality transfer in an enantiospecific Pd-catalyzed transannular cyclization
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Figure Presented. A total synthesis of rhazinilam based on a transannular cyclization strategy is described. Using a Heck reaction, the axial chirality of a halogenated 13-membered lactam can be exploited to create the quaternary chiral stereogenic center in the target molecule with high enantiospecificity.
- Gu, Zhenhua,Zakarian, Armen
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supporting information; experimental part
p. 4224 - 4227
(2010/11/17)
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- Au(I)-catalyzed annulation of enantioenriched allenes in the enantioselective total synthesis of (-)-rhazinilam
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Highly stereoselective Au(I)-catalyzed pyrrole additions to enantioenriched allenes afford a unique entry to optically active heterocycles. Asymmetric quaternary carbons can be installed with concurrent heterocycle annulation utilizing this methodology. The enantioenriched allenes are conveniently obtained by catalytic asymmetric acyl halide-aldehyde cyclocondensations and SN2′ ring opening of the resulting enantioenriched β-lactones. An enantioselective total synthesis of (-)-rhazinilam highlights the potential utility of this reaction technology in target-oriented synthesis. Copyright
- Liu, Zuosheng,Wasmuth, Andrew S.,Nelson, Scott G.
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p. 10352 - 10353
(2007/10/03)
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- Concise synthesis of (±)-Rhazinilam through direct coupling
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(Chemical Equation Presented) A concise synthesis of rhazinilam through direct, palladium-catalyzed, intramolecular coupling is described.
- Bowie Jr., Alfred L.,Hughes, Chambers C.,Trauner, Dirk
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p. 5207 - 5209
(2007/10/03)
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- Concise synthesis of (±)-rhazinilam
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2-Piperidone has been converted into (±)-rhazinilam in nine steps in 8% overall yield. The key transformation involves the conversion of the lactam 5 into the annulated pyrrole derivative 3 via the thiophenyl imine 8.
- Magnus, Philip,Rainey, Trevor
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p. 8647 - 8651
(2007/10/03)
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