Total Synthesis of (±)-Illisimonin A, a Neuroprotective Sesquiterpenoid from the Fruits of Illicium simonsii

2019 ◽  
Author(s):  
Alexander S. Burns ◽  
Scott Rychnovsky
Keyword(s):  
Total Synthesis ◽  
Cell Injury ◽  
Glucose Deprivation ◽  
Ring System ◽  
Diels Alder ◽  
Synthetic Route ◽  
Neuroprotective Effects ◽  
Carbon Framework ◽  
Highly Strained ◽  
Type 3

<p>Illisimonin A was isolated from Illicium simonsii and has a previously unreported tricyclic carbon framework. It displayed neuroprotective effects against oxygen-glucose deprivation-induced cell injury in SH-SY5Y cells. It incorporates a highly strained trans-pentalene ring system. We report the first synthesis of illisimonin A. Notable steps in the route include a 1,3-dioxa-2-silacyclohexenetemplated Diels-Alder cycloaddition and type-3 semipinacol rearrangement to generate the trans-pentalene. The final step is an iron-catalyzed C-H oxidation. The synthetic route is robust, with 94 mg prepared in a single pass.</p>

Total Synthesis of (±)-Illisimonin A, a Neuroprotective Sesquiterpenoid from the Fruits of Illicium simonsii

2019 ◽  
Author(s):  
Alexander S. Burns ◽  
Scott Rychnovsky
Keyword(s):  
Total Synthesis ◽  
Cell Injury ◽  
Glucose Deprivation ◽  
Ring System ◽  
Diels Alder ◽  
Synthetic Route ◽  
Neuroprotective Effects ◽  
Carbon Framework ◽  
Highly Strained ◽  
Type 3

<p>Illisimonin A was isolated from Illicium simonsii and has a previously unreported tricyclic carbon framework. It displayed neuroprotective effects against oxygen-glucose deprivation-induced cell injury in SH-SY5Y cells. It incorporates a highly strained trans-pentalene ring system. We report the first synthesis of illisimonin A. Notable steps in the route include a 1,3-dioxa-2-silacyclohexenetemplated Diels-Alder cycloaddition and type-3 semipinacol rearrangement to generate the trans-pentalene. The final step is an iron-catalyzed C-H oxidation. The synthetic route is robust, with 94 mg prepared in a single pass.</p>

scholarly journals Stereoselective total syntheses of (±)-sinularene and (±)-5-epi-sinularene: a general intramolecular Diels–Alder approach to tricyclic sesquiterpenes

1985 ◽  
Vol 63 (4) ◽  
pp. 993-995 ◽  
Author(s):  
Kazimierz Antczak ◽  
John F. Kingston ◽  
Alex G. Fallis
Keyword(s):  
Double Bond ◽  
Methyl Ester ◽  
Total Synthesis ◽  
Ring System ◽  
Diels Alder ◽  
Exocyclic Double Bond ◽  
Total Syntheses ◽  
Methyl Group ◽  
Secondary Hydroxyl ◽  
Selective Hydrogenolysis

Stereoselective total synthesis of (±)-sinularene and (±)-5-epi-sinularene are described. The sequence employs a "blocked" cyclopentadiene in which the cyclopropane unit also serves as a latent methyl group. Thus intramolecular [4 + 2] cycloaddition of the substituted methyl spiro[2.4]hepta-4,6-dien-1-yl)-2-pentenoate 11 affords 5-benzyloxy-6-isopropyl-8-carbomethoxytetracyclo[5.4.01,7.02,4.02,9]undec-10-ene (12) which after selective hydrogenolysis generates the tricyclo[4.4.01,6.02,8]decane (sinularene) ring system. Removal of the secondary hydroxyl function (Ph3P/CCl4/CH3CN; H2/Pd/C), reduction of the methyl ester (LiAlH4), and introduction of the exocyclic double bond (acetate pyrolysis, 550 °C) completes the synthesis of (±)-sinularene in 14 steps from cyclopentadiene. A parallel series of reactions employing the isopropyl epimer of 12 affords (±)-5-epi-sinularene.

A Thio-Diels−Alder Route to the Azocine Ring System. Total Synthesis of (±)-Otonecine

1998 ◽  
Vol 120 (15) ◽  
pp. 3613-3622 ◽  
Author(s):  
Edwin Vedejs ◽  
Rocco J. Galante ◽  
Peter G. Goekjian
Keyword(s):  
Total Synthesis ◽  
Ring System ◽  
Diels Alder

scholarly journals Synthesis of Novel N-Heterocyclic Compounds Containing 1,2,3-Triazole Ring System via Domino, “Click” and RDA Reactions

Molecules ◽  
2019 ◽  
Vol 24 (4) ◽  
pp. 772 ◽  
Author(s):  
Márta Palkó ◽  
Mohamed El Haimer ◽  
Zsanett Kormányos ◽  
Ferenc Fülöp
Keyword(s):  
Heterocyclic Compounds ◽  
Click Reaction ◽  
Triazole Ring ◽  
Heterocyclic Ring ◽  
Ring System ◽  
Diels Alder ◽  
Ring Closure ◽  
Synthetic Route ◽  
13C Nuclear Magnetic Resonance ◽  
Nmr Methods

An uncomplicated, high-yielding synthetic route has been developed to constitute complicated heterocycles, applying domino, click and retro-Diels–Alder (RDA) reaction sequences. Starting from 2-aminocarboxamides, a new set of isoindolo[2,1-a]quinazolinones was synthesized with domino ring closure. A click reaction was performed to create the 1,2,3-triazole heterocyclic ring, followed by an RDA reaction resulting in dihydropyrimido[2,1-a]isoindole-2,6-diones. The absolute configuration, concluded by the norbornene structure that served as a chiral source, remained constant throughout the transformations. The structure of the synthesized compounds was examined by 1H and 13C Nuclear Magnetic Resonance (NMR) methods.

Total Synthesis of (–)-Aristoquinoline via an Intramolecular Nitrilium Ion Cyclization

Synthesis ◽  
2021 ◽  
Author(s):  
Keith P. Reber ◽  
Priyansh D. Gujarati
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Building Block ◽  
Spectroscopic Properties ◽  
Ring System ◽  
Synthetic Route ◽  
Enantioselective Total Synthesis ◽  
Key Steps

AbstractThe enantioselective total synthesis of the alkaloid aristoquinoline has been achieved in seven steps and 26% overall yield. A new preparation of the useful synthetic building block (–)-α-terpinyl amine was also developed in order to avoid stoichiometric mercury reagents or azide-containing intermediates. Key steps in the optimized synthetic route include an intramolecular nitrilium ion cyclization to form the characteristic azabicyclo[3.3.1]nonane ring system and a dia­stereoselective reduction of the resulting imine mixture to afford the natural product. An isomer of aristoquinoline containing an exocyclic alkene was also obtained and found to exhibit unusual chromatographic and spectroscopic properties.

Taxane Diterpene Synthesis Studies. Part 2: Towards Taxinine—Enantiospecific Construction of an AB-ring Substructure Incorporating both Quaternary Carbon Centres and Attempts to Annulate the C-ring

2004 ◽  
Vol 57 (1) ◽  
pp. 53 ◽  
Author(s):  
Martin G. Banwell ◽  
Malcolm D. McLeod ◽  
Andrew G. Riches
Keyword(s):  
Total Synthesis ◽  
Cycloaddition Reaction ◽  
Ring System ◽  
Diels Alder ◽  
Biologically Active ◽  
Allylic Oxidation ◽  
Cope Rearrangement ◽  
Rearrangement Reaction ◽  
Ab Ring ◽  
Active Natural

In connection with efforts to develop an efficient total synthesis of the biologically active natural product taxinine 1, the enzymatically-derived and monochiral cis-1,2-dihydrocatechol 7 was converted, over several steps including a Diels–Alder cycloaddition reaction, into the bicyclo[2.2.2]octan-2-one 18. Reaction of the last compound with the organocerium reagent 22 afforded the 1,5-diene 23 which engaged in an anionic oxy-Cope rearrangement reaction to give, after C-methylation of the product enolate 25, bicyclo[5.3.1]undecenone 27 embodying the AB-ring system of target 1. Two methods for allylic oxidation of such products were developed and several unsuccessful attempts to effect a cyclization reaction so as to establish the taxane C-ring are described.

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