Studies Toward the Total Synthesis of (-)-Kampanol A (II): An Efficient Construction of the ABCD Ring System (I).

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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New cyclization reactions in organic syntheses

Pure and Applied Chemistry ◽

10.1351/pac200274010159 ◽

2002 ◽

Vol 74 (1) ◽

pp. 159-166 ◽

Cited By ~ 16

Author(s):

Iwao Ojima

Keyword(s):

Amino Acids ◽

Transition Metal ◽

Total Synthesis ◽

Cyclization Reactions ◽

Organic Syntheses ◽

Carbocyclic Compounds ◽

Efficient Construction ◽

Transition Metal Catalyzed ◽

Metal Catalyzed

Recent development in the transition metal-catalyzed cyclization reactions for organic syntheses in the author's laboratories is summarized, which includes (i) novel silylcarbocyclizations (SiCaCs) and carbonylative carbotricyclizations, (ii) intramolecular silylformylations and desymmerization of siloxydiynes by sequential double silylformylation, (iii) efficient total synthesis of (+)-prosopinine, (iv) enantioselective desymmetrization of aminodienes, and (iv) new and efficient routes to 1-azabicyclo[x.y.0]alkane amino acids. All these processes are catalyzed by Rh or RhCo complexes, and useful for rapid and efficient construction of a variety of heterocyclic and carbocyclic compounds. Mechanisms of these new carbocyclization and cyclohydrocarbonylation reactions are also discussed.

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