共查询到20条相似文献,搜索用时 15 毫秒
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Tianjiao Qiao Yicheng Wang Sujuan Zheng Huiying Kang Guangxin Liang 《Angewandte Chemie (International ed. in English)》2020,59(33):14111-14114
The first total syntheses of three unusual norrisolide‐type rearranged spongian diterpenes, cheloviolene C, seconorrisolide B, and seconorrisolide C, have been accomplished via a common intermediate through late‐stage ring‐scissoring. The synthesis features a Wolff ring contraction for the synthesis of the trans‐hydrindane system, and a crucial retro Diels–Alder reaction/intramolecular ene cyclization for the rapid stereoselective construction of the furo[2,3‐b]furan system, which is commonly seen in rearranged spongian diterpenes. 相似文献
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Sulfoxide‐Based Enantioselective Nazarov Cyclization: Divergent Syntheses of (+)‐Isopaucifloral F, (+)‐Quadrangularin A,and (+)‐Pallidol 下载免费PDF全文
Mei‐Lin Tang Peng Peng Zheng‐Yu Liu Jian Zhang Jian‐Ming Yu Prof. Dr. Xun Sun 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(41):14535-14539
The synthesis of enantiomerically pure 3‐aryl substituted indanones is developed using an enantioselective sulfoxide‐based Knoevenagel condensation/Nazarov cyclization procedure. After the reductive desulfonation of the methyl para‐tolyl sulfoxide‐containing chiral auxiliary under mild conditions, selected enantiomerically pure indanone is used for the divergent total syntheses of three resveratrol natural products (+)‐isopaucifloral F, (+)‐quadrangularin A, and (+)‐pallidol. 相似文献
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Short and Divergent Total Synthesis of (+)‐Machaeriol B, (+)‐Machaeriol D, (+)‐Δ8‐THC,and Analogues 下载免费PDF全文
Felix Klotter Prof. Dr. Armido Studer 《Angewandte Chemie (International ed. in English)》2015,54(29):8547-8550
Short and highly efficient stereoselective syntheses provide machaeriols and cannabinoids in a divergent approach starting from a common precursor, commercially available (S)‐perillic acid. Key features of the novel strategy are a stereospecific palladium‐catalyzed decarboxylative arylation and a one‐pot sequence comprising a stereoselective hydroboration followed by oxidation or reduction of the corresponding intermediary boranes. The divergent approach is convincingly demonstrated by the five‐step syntheses of (+)‐machaeriol B, (+)‐machaeriol D, and related analogues, and the four‐step synthesis of (+)‐Δ8‐THC and an analogue. 相似文献
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Mikls Kpir Boglrka H. Vrkuti Lszl Vgner Gergely Vrs Gyrgy Hegyi Mt Varga Andrs Mlnsi‐Csizmadia 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(31):8350-8354
Blebbistatin, the best characterized myosin II‐inhibitor, is commonly used to study the biological roles of various myosin II isoforms. Despite its popularity, the use of blebbistatin is greatly hindered by its blue‐light sensitivity, resulting in phototoxicity and photoconversion of the molecule. Additionally, blebbistatin has serious cytotoxic side effects even in the absence of irradiation, which may easily lead to the misinterpretation of experimental results since the cytotoxicity‐derived phenotype could be attributed to the inhibition of the myosin II function. Here we report the synthesis as well as the in vitro and in vivo characterization of a photostable, C15 nitro derivative of blebbistatin with unaffected myosin II inhibitory properties. Importantly, para‐nitroblebbistatin is neither phototoxic nor cytotoxic, as shown by cellular and animal tests; therefore it can serve as an unrestricted and complete replacement of blebbistatin both in vitro and in vivo. 相似文献
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Cedric L. Hugelshofer Thomas Magauer 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(42):11533-11537
The first asymmetric total synthesis of the antifeedant terpenoids (+)‐norleucosceptroid A, (−)‐norleucosceptroid B, and (−)‐leucosceptroid K has been accomplished. This highly concise synthetic route was guided by our efforts to develop a platform for the collective synthesis of a whole family of antifeedant natural products. The synthesis features a Hauser–Kraus‐type annulation followed by an unprecedented, highly efficient intramolecular dilactol aldol‐type condensation reaction to produce the 5,6,5 skeleton. The developed synthetic route proceeds for norleucosceptroid A and B in 16 steps (longest linear sequence) from known compounds. 相似文献
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A General Entry to Antifeedant Sesterterpenoids: Total Synthesis of (+)‐Norleucosceptroid A, (−)‐Norleucosceptroid B,and (−)‐Leucosceptroid K 下载免费PDF全文
M. Sc. Cedric L. Hugelshofer Dr. Thomas Magauer 《Angewandte Chemie (International ed. in English)》2014,53(42):11351-11355
The first asymmetric total synthesis of the antifeedant terpenoids (+)‐norleucosceptroid A, (?)‐norleucosceptroid B, and (?)‐leucosceptroid K has been accomplished. This highly concise synthetic route was guided by our efforts to develop a platform for the collective synthesis of a whole family of antifeedant natural products. The synthesis features a Hauser–Kraus‐type annulation followed by an unprecedented, highly efficient intramolecular dilactol aldol‐type condensation reaction to produce the 5,6,5 skeleton. The developed synthetic route proceeds for norleucosceptroid A and B in 16 steps (longest linear sequence) from known compounds. 相似文献
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Synthesis, Crystal Structures, Vibrational Spectra, and Normal Coordinate Analyses of the mer ‐Trihalogeno‐tris‐Pyridine‐Osmium(III) Complexes mer‐[OsX3Py3], X = Cl, Br, I By reaction of the hexahalogenoosmates(IV) with pyridine and iso‐amylalcohol mer‐trihalogeno‐tris‐pyridine‐osmium(III) complexes are formed and purified by chromatography. X‐ray structure determinations on single crystals have been performed of mer‐[OsBr3Py3] (monoclinic, space group P21/n, a = 9.098(5), b = 12.864(5), c = 15.632(5) Å, β = 90.216(5)°, Z = 4) and mer‐[OsI3Py3] (monoclinic, space group P21/n, a = 9.0952(17), b = 13.461(4), c = 15.891(10), β = 91.569(5)°, Z = 4). The pyridine rings are twisted propeller‐like against the N3 meridional plane with mean angles of 49° (Cl), 46° (Br), 44° (I). Based on the molecular parameters of the X‐ray structure determinations and assuming C2 point symmetry, the IR and Raman spectra are assigned by normal coordinate analysis. Due to the stronger trans influence of pyridine as compared with the halide ligands for N'–Os–X · axes significantly different valence force constants are observed in comparison with symmetrically coordinated octahedron axes: fd(OsCl) = 1.74, fd(OsCl·) = 1.49, fd(OsBr) = 1.43, fd(OsBr · ) = 1.18, fd(OsI) = 0.99, fd(OsI · ) = 0.96, fd(OsN) between 1.96 and 2.07 and fd(OsN') between 2.13 and 2.32 mdyn/Å. 相似文献
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Miklós Képiró Boglárka H. Várkuti László Végner Gergely Vörös György Hegyi Máté Varga András Málnási‐Csizmadia 《Angewandte Chemie (International ed. in English)》2014,53(31):8211-8215
Blebbistatin, the best characterized myosin II‐inhibitor, is commonly used to study the biological roles of various myosin II isoforms. Despite its popularity, the use of blebbistatin is greatly hindered by its blue‐light sensitivity, resulting in phototoxicity and photoconversion of the molecule. Additionally, blebbistatin has serious cytotoxic side effects even in the absence of irradiation, which may easily lead to the misinterpretation of experimental results since the cytotoxicity‐derived phenotype could be attributed to the inhibition of the myosin II function. Here we report the synthesis as well as the in vitro and in vivo characterization of a photostable, C15 nitro derivative of blebbistatin with unaffected myosin II inhibitory properties. Importantly, para‐nitroblebbistatin is neither phototoxic nor cytotoxic, as shown by cellular and animal tests; therefore it can serve as an unrestricted and complete replacement of blebbistatin both in vitro and in vivo. 相似文献
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Enantioselective Total Syntheses of (−)‐Rhazinilam, (−)‐Leucomidine B,and (+)‐Leuconodine F 下载免费PDF全文
Dylan Dagoneau Dr. Zhengren Xu Dr. Qian Wang Prof. Dr. Jieping Zhu 《Angewandte Chemie (International ed. in English)》2016,55(2):760-763
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. 相似文献
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Dylan Dagoneau Zhengren Xu Qian Wang Jieping Zhu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2016,128(2):770-773
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. 相似文献
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Hang Cheng Fan‐Hao Zeng Xue Yang Yin‐Juan Meng Liang Xu Feng‐Peng Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2016,128(1):400-404
The first total syntheses of the architecturally complex atisane‐type diterpenes and biogenetically related atisine‐type diterpenoid alkaloids (±)‐spiramilactone B, (±)‐spiraminol, (±)‐dihydroajaconine, and (±)‐spiramines C and D are reported. Highlights of the synthesis include a late‐stage biomimetic transformation of spiramilactone B, a facile formal lactone migration from the pentacyclic skeleton of spiramilactone E, a highly efficient and diastereoselective 1,7‐enyne cycloisomerization to construct the functionalized tetracyclic atisane skeleton, and a tandem retro‐Diels–Alder/intramolecular Diels–Alder sequence to achieve the tricyclo[6.2.2.0] ring system. 相似文献
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Collective Total Syntheses of Atisane‐Type Diterpenes and Atisine‐Type Diterpenoid Alkaloids: (±)‐Spiramilactone B, (±)‐Spiraminol, (±)‐Dihydroajaconine,and (±)‐Spiramines C and D 下载免费PDF全文
Hang Cheng Fan‐Hao Zeng Xue Yang Yin‐Juan Meng Prof. Liang Xu Prof. Feng‐Peng Wang 《Angewandte Chemie (International ed. in English)》2016,55(1):392-396
The first total syntheses of the architecturally complex atisane‐type diterpenes and biogenetically related atisine‐type diterpenoid alkaloids (±)‐spiramilactone B, (±)‐spiraminol, (±)‐dihydroajaconine, and (±)‐spiramines C and D are reported. Highlights of the synthesis include a late‐stage biomimetic transformation of spiramilactone B, a facile formal lactone migration from the pentacyclic skeleton of spiramilactone E, a highly efficient and diastereoselective 1,7‐enyne cycloisomerization to construct the functionalized tetracyclic atisane skeleton, and a tandem retro‐Diels–Alder/intramolecular Diels–Alder sequence to achieve the tricyclo[6.2.2.0] ring system. 相似文献