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 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.

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.

Studies toward the total synthesis of nakiterpiosin: construction of the CDE ring system by a transannular Diels–Alder strategy

2007 ◽  
Vol 48 (31) ◽  
pp. 5465-5469 ◽  
Author(s):  
Tomonori Ito ◽  
Masahiro Ito ◽  
Hirokazu Arimoto ◽  
Hiroyoshi Takamura ◽  
Daisuke Uemura
Keyword(s):  
Total Synthesis ◽  
Ring System ◽  
Diels Alder

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>

ChemInform Abstract: A Thio-Diels-Alder Route to the Azocine Ring System. Total Synthesis of (.+-.)-Otonecine.

ChemInform ◽  
2010 ◽  
Vol 29 (33) ◽  
pp. no-no
Author(s):  
E. VEDEJS ◽  
R. J. GALANTE ◽  
P. G. GOEKJIAN
Keyword(s):  
Total Synthesis ◽  
Ring System ◽  
Diels Alder

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 the Diterpenoid Alkaloid Arcutinidine Using a Strategy Inspired by Chemical Network Analysis

2019 ◽  
Author(s):  
Kyle Owens ◽  
Shelby McCowen ◽  
Katherine Blackford ◽  
Sohei Ueno ◽  
Yasuo Hirooka ◽  
...  
Keyword(s):  
Natural Products ◽  
Network Analysis ◽  
Total Synthesis ◽  
Ring System ◽  
Diels Alder ◽  
Diterpenoid Alkaloids ◽  
Oxidative Dearomatization ◽  
Diterpenoid Alkaloid ◽  
Fused Ring ◽  
Fused Ring System

Arcutinidine and other arcutinidine-type diterpenoid alkaloids feature an intricate polycyclic, bridged framework with unusual connectivity. A chemical network analysis approach to the arcutane skeleton enabled the identification of highly simplifying retrosynthetic disconnections, which indicated that the caged structure could arise from a simpler fused ring system. On this basis, a total synthesis of arcutinidine is reported herein, featuring an unprecedented oxopyrrolium Diels–Alder cycloaddition which furnishes a key tetracyclic intermediate. In addition, the synthesis utilizes a diastereoselective oxidative dearomatization/cycloaddition sequence and a SmI2-mediated C–C coupling to forge the bridged framework of the natural products. This synthetic plan may also enable future investigations into the biosynthetic relationships between the arcutanes, the related diterpenoid atropurpuran, and other diterpenoid alkaloids.

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