Diastereoselective Total Synthesis of (±)-Schindilactone A, Part 1: Construction of the ABC and FGH Ring Systems and Initial Attempts to Construct the CDEF Ring System

ABSTRACTThis paper models maximum entropy configurations of idealized gravitational ring systems. Such configurations are of interest because systems generally evolve toward an ultimate state of maximum randomness. For simplicity, attention is confined to ultimate states for which interparticle interactions are no longer of first order importance. The planets, in their orbits about the sun, are one example of such a ring system. The extent to which the present approximation yields insight into ring systems such as Saturn's is explored briefly.

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Concise Total Synthesis of Curvulone B

Synlett ◽

10.1055/a-1297-6838 ◽

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.

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

Chemischer Informationsdienst ◽

10.1002/chin.197552277 ◽

1975 ◽

Vol 6 (52) ◽

pp. no-no

Author(s):

S. BARCZA ◽

C. W. HOFFMAN

Keyword(s):

Total Synthesis ◽

Ring System

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Short, enantioselective, gram-scale synthesis of (−)-zephyranthine

Chemical Science ◽

10.1039/d1sc03147c ◽

2021 ◽

Author(s):

Yuxiang Zhao ◽

Yanren Zhu ◽

Guolan Ma ◽

Qi Wei ◽

Shaoxiong Yang ◽

...

Keyword(s):

Total Synthesis ◽

Functional Group ◽

Ring System ◽

System Construction ◽

Synthesis Design

A reasonable synthesis design by strategically integrating functional group manipulation into the ring system construction resulted in a short, enantioselective, gram-scale total synthesis of (−)-zephyranthine.

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

Canadian Journal of Chemistry ◽

10.1139/v85-166 ◽

1985 ◽

Vol 63 (4) ◽

pp. 993-995 ◽

Cited By ~ 8

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.

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Synthesis of Pyrazolofuropyrazine via One-Pot SNAr Reaction and Intramolecular Direct C–H Arylation

Synthesis ◽

10.1055/s-0036-1591885 ◽

2018 ◽

Vol 50 (07) ◽

pp. 1493-1498 ◽

Cited By ~ 3

Author(s):

Shinichiro Fuse ◽

Hiroyuki Nakamura ◽

Megumi Inaba ◽

Shinichi Sato ◽

Manjusha Joshi

Keyword(s):

Drug Discovery ◽

Rapid Development ◽

Ring System ◽

Biologically Active ◽

Drug Candidate ◽

One Pot ◽

Ring Systems ◽

Drug Candidates ◽

Fused Ring ◽

Snar Reaction

Fused-ring systems containing heterocycles are attractive templates for drug discovery. Biologically active 6-5-5+6 fused-ring systems that possess heterocycles are available, but these require a relatively large number of synthetic steps for preparation. Therefore, pyrazolofuropyrazine was designed as a 6-5-5+6 ring system template that incorporates ready accessibility for drug discovery. Pyrazolofuropyrazines were successfully constructed in only a few steps via one-pot SNAr reaction/intramolecular C–H direct arylation. As a drug candidate, pyrazolofuropyrazine has earned a favorable LogP, although significant biological activity has yet to be established; the ready accessibility of pyrazolofuropyrazine template, however, offers an opportunity for the rapid development of promising new drug candidates.

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