Total synthesis of montanine-type Amaryllidaceae alkaloids, which possess a 5,11-methanomorphanthridine ring system, through cyclization with sodium bis(2-methoxyethoxy)aluminum hydride (SMEAH): the first stereoselective total syntheses of (.+-.)-montanine, (.+-.)-coccinine, (.+-.)-O-acetylmontanine, (.+-.)-pancracine, and (.+-.)-brunsvigine

1992 ◽  
Vol 57 (26) ◽  
pp. 7285-7295 ◽  
Author(s):  
Miyuki Ishizaki ◽  
Osamu Hoshino ◽  
Yoichi Iitaka
Keyword(s):  
Total Synthesis ◽  
Aluminum Hydride ◽  
Ring System ◽  
Total Syntheses ◽  
Amaryllidaceae Alkaloids

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.

scholarly journals Evolution of the Total Syntheses of Batzellasides the First Marine Piperidine Iminosugar

2013 ◽  
Vol 8 (7) ◽  
pp. 1934578X1300800
Author(s):  
Tetsuya Sengoku ◽  
Jolanta Wierzejska ◽  
Masaki Takahashi ◽  
Hidemi Yoda
Keyword(s):  
Total Synthesis ◽  
First Generation ◽  
Ring System ◽  
Piperidine Ring ◽  
Total Syntheses ◽  
Asymmetric Dihydroxylation ◽  
Biological Studies ◽  
The Common ◽  
Absolute Stereochemistry

Batzellasides A-C are C-alkylated piperidine iminosugars isolated from a sponge Batzella sp. The first total synthesis of (+)-batzellaside B was achieved by employing a chiral pool approach starting from L-arabinose for the construction of a piperidine ring system. Subsequently a practical second-generation synthesis was developed by utilizing a Sharpless asymmetric dihydroxylation for the preparation of the common piperidine intermediate elaborated in the first-generation synthesis. The overall yield of batzellaside B was improved to 3.3% by introducing the exocyclic C8 stereocenter via facial selective hydride addition to a linear ketone. These syntheses allowed for the determination of the absolute stereochemistry of this natural product as well as for providing precious samples which would pave the way for further biological studies.

scholarly journals Concise total syntheses of (±)-mesembrane and (±)-crinane

2015 ◽  
Vol 13 (12) ◽  
pp. 3585-3588 ◽  
Author(s):  
Mrinal Kanti Das ◽  
Subhadip De ◽  
Shubhashish Shubhashish ◽  
Alakesh Bisai
Keyword(s):  
Total Synthesis ◽  
Claisen Rearrangement ◽  
Unified Approach ◽  
Total Syntheses ◽  
Amaryllidaceae Alkaloids ◽  
Quaternary Stereocenters

A unified approach to the Amaryllidaceae alkaloids having a cis-3a-aryloctahydroindole scaffold is developed via a key Eschenmoser–Claisen rearrangement of all-carbon quaternary stereocenters present in these alkaloids. Utilizing this strategy, a concise total synthesis of (±)-mesembrane and (±)-crinane is achieved.

Concise Total Synthesis of Curvulone B

Synlett ◽  
2020 ◽  
Author(s):  
Debendra K. Mohapatra ◽  
Shivalal Banoth ◽  
Utkal Mani Choudhury ◽  
Kanakaraju Marumudi ◽  
Ajit C. Kunwar
Keyword(s):  
Total Synthesis ◽  
Stereoselective Synthesis ◽  
Ring System ◽  
Bond Forming ◽  
Cross Metathesis ◽  
Bond Forming Reactions ◽  
Key Steps

AbstractA concise and convergent stereoselective synthesis of curvulone B is described. The synthesis utilized a tandem isomerization followed by C–O and C–C bond-forming reactions following Mukaiyama-type aldol conditions for the construction of the trans-2,6-disubstituted dihydropyran ring system as the key steps. Other important features of this synthesis are a cross-metathesis, epimerization, and Friedel–Crafts acylation.

ChemInform Abstract: TOTAL SYNTHESIS OF THE 6-SILASTEROID RING SYSTEM

1975 ◽  
Vol 6 (52) ◽  
pp. no-no
Author(s):  
S. BARCZA ◽  
C. W. HOFFMAN
Keyword(s):  
Total Synthesis ◽  
Ring System

scholarly journals Xylochemical Synthesis and Biological Evaluation of Shancigusin C and Bletistrin G

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3224
Author(s):  
Leander Geske ◽  
Ulrich Kauhl ◽  
Mohamed E. M. Saeed ◽  
Anja Schüffler ◽  
Eckhard Thines ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Biological Activities ◽  
Biological Evaluation ◽  
Aromatic Substitution ◽  
Substitution Reactions ◽  
Total Syntheses ◽  
Wittig Olefination ◽  
Starting Point ◽  
Perkin Reaction ◽  
Synthesis And Biological Evaluation

The biological activities of shancigusin C (1) and bletistrin G (2), natural products isolated from orchids, are reported along with their first total syntheses. The total synthesis of shancigusin C (1) was conducted by employing the Perkin reaction to forge the central stilbene core, whereas the synthesis of bletistrin G (2) was achieved by the Wittig olefination followed by several regioselective aromatic substitution reactions. Both syntheses were completed by applying only renewable starting materials according to the principles of xylochemistry. The cytotoxic properties of shancigusin C (1) and bletistrin G (2) against tumor cells suggest suitability as a starting point for further structural variation.

Total syntheses and antiproliferative activities of prenostodione and its analogues

2021 ◽  
Author(s):  
Aldahir Ramos Orea ◽  
María Teresa Ramírez-Apan ◽  
Rosa M. Chávez-Santos ◽  
Rodrigo Aguayo-Ortiz ◽  
Clara I Espitia ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Total Synthesis ◽  
Indole Alkaloid ◽  
Total Syntheses ◽  
Antiproliferative Activities

A high-yielding total synthesis of the indole alkaloid prenostodione was completed in 4 steps and 44% overall yield from 1H-indole-3-carboxylic acid. The expedient syntheses of prenostodiones containing distinct substituents at...

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