Studies in Sigmatropic Rearrangement:  Synthesis of a [6,6]Pyranothiopyran Ring System by Sequential Claisen Rearrangement and Pyridine Hydrotribromide Mediated Regioselective “6-Endo” Cyclization†

2002 ◽  
Vol 4 (16) ◽  
pp. 2629-2631 ◽  
Author(s):  
K. C. Majumdar ◽  
U. K. Kundu ◽  
S. K. Ghosh
Keyword(s):  
Claisen Rearrangement ◽  
Ring System ◽  
Sigmatropic Rearrangement

Regiospecific preparation of 10-allyl-1-ketoquinolizidine and an unexpected disproportionation during its Wolff–Kischner reduction

1979 ◽  
Vol 57 (16) ◽  
pp. 2114-2117 ◽  
Author(s):  
John M. McIntosh
Keyword(s):  
Ring System ◽  
Sigmatropic Rearrangement ◽  
High Yield ◽  
Reaction Conditions ◽  
Fused Ring ◽  
Fused Ring System

Regiospecific formation of 10-allyl-1-ketoquinolizidine (7) is achieved in high yield by a [2.3] sigmatropic rearrangement of N-allyl-1-ketoquinolizidinium bromide (6). Wolff–Kischner reduction of 7 affords 10-allylquinolizidine (8) contaminated by the 10-propyl and 10-ethynyl analogs in amounts which depend on the reaction conditions. The carbon-13 spectrum of 8 indicates a trans-fused ring system with an axial substituent at C-10.

Stereoselective Construction of an Unprecedented 7−8 Fused Ring System in Micrandilactone A by [3,3]-Sigmatropic Rearrangement

2008 ◽  
Vol 10 (4) ◽  
pp. 665-668 ◽  
Author(s):  
Yan-Dong Zhang ◽  
Wei-Wu Ren ◽  
Yu Lan ◽  
Qing Xiao ◽  
Kai Wang ◽  
...  
Keyword(s):  
Ring System ◽  
Sigmatropic Rearrangement ◽  
Fused Ring ◽  
Fused Ring System

Sequential O-Arylation/Lanthanide(III)-Catalyzed [3,3]-Sigmatropic Rearrangement of Bromo-Substituted Allylic Alcohols

Synlett ◽  
2017 ◽  
Vol 28 (20) ◽  
pp. 2865-2870 ◽  
Author(s):  
Timothy Ramadhar ◽  
Jun-ichi Kawakami ◽  
Robert Batey
Keyword(s):  
Claisen Rearrangement ◽  
Cross Coupling ◽  
Sigmatropic Rearrangement ◽  
Mitsunobu Reaction ◽  
Allylic Alcohols ◽  
Aryl Ether ◽  
Claisen Rearrangements ◽  
Snar Reaction ◽  
Aryl Ethers

Lanthanide(III)-catalyzed aryl-Claisen rearrangement of substrates bearing halo-substituted allyl groups, specifically 2-bromoallyl aryl ethers, afford ortho-2-bromoallylphenols. Aryl ether substrates were synthesized from brominated allylic alcohols via Mitsunobu reaction, Cu(II)-catalyzed arylation using potassium aryltrifluoroborate salts, or SNAr reaction. Aryl-Claisen rearrangements proceeded in moderate to excellent yields using Eu(III) catalysis. The alkenylbromide functionality remains intact, illustrating the compatibility of synthetically important alkenylhalides during C–O/C–C σ-bond migration processes. Subsequent derivatization of the ortho-2-bromoallylphenol products through O-alkylation or C-arylation/alkenylation via Suzuki–Miyaura cross-coupling demonstrate the potential to access densely-functionalized molecules.

Enantioselective Construction of a 2,8-Dioxabicyclo[3.2.1]octane Ring System via [2,3]-Sigmatropic Rearrangement of Oxonium Ylide Using Chiral Dirhodium(II) Carboxylates

2009 ◽  
Vol 38 (5) ◽  
pp. 488-489 ◽  
Author(s):  
Naoyuki Shimada ◽  
Seiichi Nakamura ◽  
Masahiro Anada ◽  
Motoo Shiro ◽  
Shunichi Hashimoto
Keyword(s):  
Ring System ◽  
Sigmatropic Rearrangement ◽  
Oxonium Ylide

scholarly journals Asymmetric Total Synthesis of (+)-21-epi-Eburnamonine Via a Photocatalytic Radical Cascade Reaction

2020 ◽  
Author(s):  
Yuan Huang ◽  
Fanglin Xue ◽  
Hengmao Liu ◽  
Fei Xue ◽  
Xiao-Yu Liu ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Visible Light ◽  
Claisen Rearrangement ◽  
Cascade Reaction ◽  
Ring System ◽  
Asymmetric Total Synthesis ◽  
Radical Cascade ◽  
Key Features ◽  
Quaternary Stereocenter ◽  
Visible Light Photocatalytic

Abstract An asymmetric total synthesis of (+)-21-epi-eburnamonine has been achieved. Key features of the synthesis include a visible-light photocatalytic intra-/intramolecular radical cascade reaction to assemble the tetracyclic ABCD ring system, and a highly diastereoselective Johnson-Claisen rearrangement to establish the C20 all-carbon quaternary stereocenter. Graphic Abstract

Synthetic Studies toward Tubiferal A: Asymmetric Synthesis of a Model ABC-ring Compound

Synlett ◽  
2021 ◽  
Author(s):  
Yuki Yukutake ◽  
Takahiro Hiramatsu ◽  
Ryusei Itoh ◽  
Kazutada Ikeuchi ◽  
Takahiro Suzuki ◽  
...  
Keyword(s):  
Asymmetric Synthesis ◽  
Claisen Rearrangement ◽  
Ring System ◽  
Alkylation Reaction ◽  
Ring Model ◽  
Stereoselective Addition ◽  
Stereogenic Centers ◽  
Rearrangement Reaction ◽  
Synthetic Studies ◽  
Ab Ring

Synthetic studies on an ABC-ring model of Tubiferal A, a triterpenoid isolated from the fruit bodies of the Tubifera dimorphotheca myxomycete, are described. The stereogenic centers at the angular positions were constructed through the stereoselective addition of a C-ring allylborane followed by an Eschenmoser–Claisen rearrangement reaction prior to the formation of the AB-ring system by a double intramolecular alkylation reaction of a dichloro nitrile intermediate.

scholarly journals Synthesis of the B-seco limonoid core scaffold

2014 ◽  
Vol 10 ◽  
pp. 194-208 ◽  
Author(s):  
Hanna Bruss ◽  
Hannah Schuster ◽  
Rémi Martinez ◽  
Markus Kaiser ◽  
Andrey P Antonchick ◽  
...  
Keyword(s):  
Natural Products ◽  
Claisen Rearrangement ◽  
Sigmatropic Rearrangement ◽  
Detailed Model ◽  
Model Studies ◽  
Sterically Demanding

Synthetic investigations towards the structurally complex and highly decorated framework of B-seco limonoid natural products by means of a [3,3]-sigmatropic rearrangement are described. Detailed model studies reveal, that an Ireland–Claisen rearrangement can be employed to construct the central C9–C10 bond thereby giving access to the B-seco limonoid scaffold. However, application of the developed strategy ended up failing in more complex and sterically demanding systems.

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