A stereoselective asymmetric synthesis of antibiotic (-)-Fumagillol using claisen rearrangement and intramolecular ester enolate alkylation as key steps

2005 ◽  
Vol 28 (2) ◽  
pp. 129-141 ◽  
Author(s):  
Deukjoon Kim ◽  
Soon Kil Ahn ◽  
Hoon Bae ◽  
Hak Sung Kim
Keyword(s):  
Asymmetric Synthesis ◽  
Claisen Rearrangement ◽  
Enolate Alkylation ◽  
Ester Enolate ◽  
Key Steps

A total synthesis of (−)-reiswigin a via sequential claisen rearrangement-intramolecular ester enolate alkylation

1994 ◽  
Vol 35 (43) ◽  
pp. 7957-7960 ◽  
Author(s):  
Deukjoon Kim ◽  
Kye Jung Shin ◽  
Ik Yoen Kim ◽  
Sang Woo Park
Keyword(s):  
Total Synthesis ◽  
Claisen Rearrangement ◽  
Enolate Alkylation ◽  
Ester Enolate

Copper-catalyzed alkynylation/annulation cascades of N-allyl ynamides: regioselective access to medium-sized N-heterocycles

2021 ◽  
Vol 8 (1) ◽  
pp. 18-24
Author(s):  
Xu-Heng Yang ◽  
Jian Huang ◽  
Fang Wang ◽  
Zhuoliang Liu ◽  
Yujiao Li ◽  
...  
Keyword(s):  
Claisen Rearrangement ◽  
Synthetic Strategy ◽  
Key Steps

A synthetic strategy based on sequential application of aza-Claisen rearrangement, C–H functionalization, C–N coupling and cyclization as key steps has been developed for the synthesis of 6-, 7-, 8-, and 9-membered rings N-heterocycles.

scholarly journals Asymmetric Synthesis of the C15–C32 Fragment of Alotamide and Determination of the Relative Stereochemistry

Marine Drugs ◽  
2018 ◽  
Vol 16 (11) ◽  
pp. 414 ◽  
Author(s):  
Hao-yun Shi ◽  
Yang Xie ◽  
Pei Hu ◽  
Zi-qiong Guo ◽  
Yi-hong Lu ◽  
...  
Keyword(s):  
Asymmetric Synthesis ◽  
Nmr Spectra ◽  
Calcium Influx ◽  
Aldol Reaction ◽  
13C Nmr Spectra ◽  
Marine Cyanobacterium ◽  
Relative Stereochemistry ◽  
Key Steps ◽  
Relative Structure

Alotamide is a cyclic depsipetide isolated from a marine cyanobacterium and possesses a unique activation of calcium influx in murine cerebrocortical neurons (EC50 4.18 µM). Due to its limited source, the three stereocenters (C19, C28, and C30) in its polyketide fragment remain undetermined. In this study, the first asymmetric synthesis of its polyketide fragment was achieved. Four relative possible diastereomers were constructed with a boron-mediated enantioselective aldol reaction and Julia–Kocienski olefination as the key steps. Comparison of 13C NMR spectra revealed the relative structure of fragment C15–C32 of alotamide.

Alkaloid Synthesis: Indolizidine 223AB (Cha), Lepadiformine (Kim), Kainic Acid (Fukuyama), Gephyrotoxin (Smith), Premarineosin A (Reynolds)

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Kainic Acid ◽  
Claisen Rearrangement ◽  
State University ◽  
University Of Oxford ◽  
Wayne State University ◽  
Peking University ◽  
Portland State University ◽  
National University ◽  
Ester Enolate ◽  
Indolizidine 223Ab

Jin Kun Cha of Wayne State University prepared (Org. Lett. 2014, 16, 6208) the allene 1 by SN2′ coupling of a cyclopropanol with a propargylic tosylate. Silver-mediated cyclization converted 1 into 2, that was reduced with diimide to the Dendrobates alka­loid indolizidine 223AB 3. Sanghee Kim of Seoul National University observed (Chem. Eur. J. 2014, 20, 17433) high diastereoselectivity in the Ireland–Claisen rearrangement of 4 to 5. The acid 5 was the key intermediate for the synthesis of the tunicate alkaloid lepadiformine 6. Tohru Fukuyama of Nagoya University also used (Eur. J. Org. Chem. 2014, 4823) an ester enolate Claisen rearrangement to set the relative and absolute configuration of 7. Pd-catalyzed cyclization then led to 8, that was carried on to the excitatory amino acid receptor agonist kainic acid 9. Gephyrotoxin 12 was so named because it incorporates structural elements from two different classes of the Dendrobates alkaloids. Martin D. Smith of the University of Oxford envisioned (Angew. Chem. Int. Ed. 2014, 53, 13826) the cascade cyclization of deprotected 10 to give, after reduction, the ketone 11. Zhen Yang of the Peking University Shenzhen Graduate School showed (Chem. Eur. J. 2014, 20, 12881) that the Rh carbene derived from 13 readily cyclized to an imine. The facial selectivity of the addition of the Grignard reagent 14 to that imine depended on the temperature of the reaction. At room temperature, 15 was formed. At low temperature, the other diastereomer predominated. Ring-closing metathesis was used for the elaboration of 15 to the Stemona alkaloid tuberostemospiroline 16. Kevin A. Reynolds of Portland State University prepared (J. Org. Chem. 2014, 79, 11674) 19 by condensation of the pyrrole 17 with the aldehyde 18. The biosyn­thetic enzyme, that they had overexpressed, oxidized 19 to the antimalarial alkaloid permarineosin A 20.

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.

Ring-Closing Metathesis Approach to Cage Propellanes Containing Oxepane and Tetrahydrofuran Hybrid System

Synthesis ◽  
2017 ◽  
Vol 49 (24) ◽  
pp. 5339-5350 ◽  
Author(s):  
Sambasivarao Kotha ◽  
Subba Cheekatla ◽  
Darshan Mhatre
Keyword(s):  
Claisen Rearrangement ◽  
Alder Reaction ◽  
Diels Alder ◽  
Ring Closing Metathesis ◽  
Cage Compounds ◽  
Transannular Cyclization ◽  
Diels Alder Reaction ◽  
Grignard Addition ◽  
Key Steps ◽  
First Time

The preparation of a variety of structurally interesting oxygenated cage compounds involving atom-economic processes such as Claisen rearrangement, Diels–Alder reaction, [2+2] photocycloaddition, and ring-closing metathesis (RCM) as key steps is reported. For the first time, oxepane ring system is introduced in cage framework using olefin metathesis as a key step. These cage systems assembled here are difficult to prepare by traditional methods. The synthetic sequence described here opens up new routes to higher order polycycles containing heteroatoms without the involvement of protecting groups. Transannular cyclization observed during Grignard addition and the RCM protocol used here may be applicable to generate unknown oxygenated cage systems.

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