Asymmetric Synthesis of (−)-Trichodiene. Generation of Vicinal Stereogenic Quaternary Centers via the Thio-Claisen Rearrangement

1998 ◽  
Vol 120 (22) ◽  
pp. 5453-5457 ◽  
Author(s):  
René M. Lemieux ◽  
A. I. Meyers
Keyword(s):  
Asymmetric Synthesis ◽  
Claisen Rearrangement ◽  
Quaternary Centers

Intramolecular Diels-Alder Cycloaddition: 7-Isocyanoamphilecta- 11(20),15-diene (Miyaoka), (–)-Scabronine G (Kanoh), Basiliolide B (Stoltz), Hirsutellone B (Uchiro), Echinopine A (Chen)

2015 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Neurotrophic Factors ◽  
Claisen Rearrangement ◽  
Diels Alder ◽  
Relative Configuration ◽  
Intramolecular Cycloaddition ◽  
Quaternary Centers ◽  
Astrocytoma Cells ◽  
National University ◽  
Seoul National University ◽  
1321N1 Astrocytoma

The amphilectane diterpenes, exemplified by 7-isocyanoamphilecta-11(20),15-diene 3, have been little investigated. In the course of a synthesis of 3, Hiroaki Miyaoka of the Tokyo University of Pharmacy and Life Sciences took advantage (Synlett 2011, 547) of the kinetic enolization and silylation of 1 to convert it into a trienone that spontaneously cyclized to 2. Scabronine G 6, isolated from the mushroom Sarcodon scabrosus, was found to enhance the secretion of neurotrophic factors from 1321N1 astrocytoma cells. To set the absolute configuration of the two quaternary centers that are 1, 4 on the cyclohexane ring of 6, Naoki Kanoh and Yoshiharu Iwabuchi of Tohoku University cyclized (Org. Lett. 2011, 13, 2864) 4 to 5. Although described by the authors as a double Michael addition, this transformation has the same connectivity as an intramolecular Diels-Alder cycloaddition. The diterpenes isolated from the genus Thapsia, represented by basiliolide B 9, induce rapid mobilization of intracellular Ca2+ stores. Brian M. Stoltz of Caltech effected (Angew. Chem. Int. Ed. 2011, 50, 3688) Claisen rearrangement of 7 to give an intermediate that cyclized to 8 as a mixture of diastereomers. A significant challenge in the synthesis was the assembly of the delicate enol ether/lactone of 9. Hirsutellone B 12, isolated from Hirsutella nivea, shows significant antituberculosis activity. Hiromi Uchiro of the Tokyo University of Science found it useful (Org. Lett. 2011, 13, 6268) to protect the intermediate unsaturated keto ester by intermolecular cycloaddition with pentamethylcyclopentadiene before constructing the triene of 10. Simple thermolysis reversed the intermolecular addition, opening the way to intramolecular cycloaddition to give 11. The tetracyclic ring system of the diterpene echinopine A 15 represents a substantial synthetic challenge. David Y.-K. Chen of Seoul National University approached this problem (Org. Lett. 2011, 13, 5724) by Pd-mediated cyclization of 13 to the diene, which then underwent intramolecular Diels-Alder cycloaddition to give 14, with control of the relative configuration of two of the three ternary centers of 15. Double bond migration followed by oxidative cleavage of the resulting cyclohexenone then set the stage for the intramolecular cyclopropanation that completed the synthesis of 15.

Asymmetric Synthesis of 2,3,6-Trisubstituted Piperidines via Baylis–Hillman Adducts and Lithium Amide through Domino Reaction

Synlett ◽  
2019 ◽  
Vol 31 (06) ◽  
pp. 600-604 ◽  
Author(s):  
Mateo M. Salgado ◽  
Alejandro Manchado ◽  
Carlos T. Nieto ◽  
David Díez ◽  
Narciso M. Garrido
Keyword(s):  
Amino Acid ◽  
Asymmetric Synthesis ◽  
Claisen Rearrangement ◽  
Domino Reaction ◽  
Amino Acid Derivative ◽  
Side Chain ◽  
Lithium Amide ◽  
Stereochemical Control ◽  
Asymmetric Michael Addition ◽  
Polysubstituted Piperidines

A convenient asymmetric synthesis of methyl (2S,3S,6R)-6-(4-fluorophenyl)-2-(4-hydroxyphenyl)-piperidine-3-carboxylate is described, starting from Baylis–Hillman adducts. The route involves a domino process: allylic acetate rearrangement, stereoselective Ireland–Claisen rearrangement and asymmetric Michael addition, which provides a δ-amino acid derivative with full stereochemical control. A subsequent chemoselective transformation of one of the side-chain groups allows an effective cyclization leading to biologically interesting polysubstituted piperidines in which the 2,6-aryl groups could be attached sequentially.

Asymmetric Synthesis of a Hydroxylated Nine-membered Lactone from Tartaric Acid using the Claisen Rearrangement

2010 ◽  
Vol 63 (3) ◽  
pp. 529 ◽  
Author(s):  
Leon S.-M. Wong ◽  
Kathleen A. Turner ◽  
Jonathan M. White ◽  
Andrew B. Holmes ◽  
John H. Ryan
Keyword(s):  
Natural Products ◽  
Asymmetric Synthesis ◽  
Tartaric Acid ◽  
Claisen Rearrangement ◽  
Cyclic Carbonate ◽  
Thermal Elimination ◽  
Ketene Acetal ◽  
Medium Ring

The synthesis of a hydroxylated vinyl-appended lactone, in five synthetic steps from tartaric acid, is reported. The C2-symmetrical bis-vinyl diol 12 was converted into the ketene acetal 14 via methylenation of the cyclic carbonate 13 or thermal elimination of benzeneselenenic acid from the selenoxide 17. In both cases, the in situ generated ketene acetal 14 underwent spontaneous Claisen rearrangement to give the nine-membered lactone (+)-15. Lactones of this type are potentially advanced precursors to simplified eleutherobin analogues or other medium-ring lactone natural products.

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.

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