Terpenoids to terpenoids: enantioselective construction of 5,6-, 5,7-, and 5,8-fused bicyclic systems. Application to the total synthesis of isodaucane sesquiterpenes and dolastane diterpenes

Mehta, Goverdhan; Krishnamurthy, N.; Karra, Srinivas

doi:10.1021/ja00015a034

Cited by 104 publications

(30 citation statements)

References 4 publications

(8 reference statements)

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“…However, the intermediary alcohol 5 h' was readily oxidized (IBX = 2-iodoxybenzoic acid), affording the desired cycloheptanone 5 h. The reaction proceeded with perfect diastereoselectivity, which is expected due to better shielding at the concave bottom face of the carbocycle. [19] In the same way, allyltrimethylsilane could be used to perform a diastereoselective carbon-carbon bond-formation reaction. Product 6 b was obtained in 76 % yield (d.r.…”

Section: Methodsmentioning

confidence: 99%

[2+2] Photocycloaddition of 3‐Alkenyloxy‐2‐cycloalkenones: Enantioselective Lewis Acid Catalysis and Ring Expansion

Brimioulle

Bach

2014

Angew Chem Int Ed

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By application of substoichiometric amounts (50 mol %) of a chiral Lewis acid, the intramolecular [2+2] photocycloaddition of the title compounds was achieved with high enantioselectivity (up to 94 % ee). Upon cleavage of the cyclobutane ring the resulting tricyclic products underwent ring-expansion reactions under acidic conditions and formed anellated seven- or eight-membered-ring systems without racemization. The ring expansion could be combined with a diastereoselective reduction (triethylsilane) or allylation (allyltrimethylsilane) upon BF3 catalysis (48-87 % yield).

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Section: Methodsmentioning

confidence: 99%

[2+2] Photocycloaddition of 3‐Alkenyloxy‐2‐cycloalkenones: Enantioselective Lewis Acid Catalysis and Ring Expansion

Brimioulle

Bach

2014

Angew Chem Int Ed

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“…2), a natural product first isolated from Spanish Eucalyptus globulus in 1947 5 and aldehyde 5 (Fig. 4), an important intermediate in several natural product syntheses [6][7][8][9][10][11] ( Fig. 1), from limonene-oxide 1 (Scheme 1).…”

Section: Introductionmentioning

confidence: 99%

A Novel Synthesis of 1-Acetyl-4-Isopropenyl-1-Cyclopentene by Chemoselective Cyclization of 4-Methyl-3-(Oxobutyl)-4-Pentenal: An Important Intermediate for Natural Product Synthesis

Castro¹,

Kover²,

Kover³

et al. 1999

J. Braz. Chem. Soc.

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Neste artigo apresentamos a oxidação direta do epóxi-limoneno 1 com KIO4 em água como uma melhor alternativa para se obter o ceto-aldeído 3, um importante intermediário na síntese de produtos naturais. O ceto-aldeído 3 é ciclizado com Al2O3-ácido de forma quimosseletiva produzindo, preferencialmente, a cetona 4. Estas duas reações elevam o rendimento total da síntese da cetona 4 para 70% em comparação com 8% pelo método citado na literatura 1 . This article presents the direct oxidation of limonene-oxide 1 with KIO4 in water, which is the best way to obtain the keto-aldehyde 3, an important intermediate in natural product synthesis. The cyclization of keto-aldehyde 3 with acidic Al2O3 proceeds chemoselectively to give ketone 4. These two reactions together increase the overall yield of ketone 4 to about 70% compared to 8% previously reported in the literature 1 .

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“…Recent synthetic approaches to the diterpenes the files. isoamijiol (1) [11] and taxol (2) [12] from (ϩ)-limonene (3) and Figure 1. View of the screen during the input of the target skeleton (Ϫ)-β-patchoulene oxide (4), respectively, are two examples that illustrate this point (Scheme 1).…”

Section: Introductionmentioning

confidence: 99%

Computer-Aided Organic Synthesis – SESAM: A Simple Program to Unravel “Hidden” Restructured Starting Materials Skeleta in Complex Targets

Mehta

Barone²,

Chanon³

1998

Eur. J. Org. Chem.

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Terpenoids to terpenoids: enantioselective construction of 5,6-, 5,7-, and 5,8-fused bicyclic systems. Application to the total synthesis of isodaucane sesquiterpenes and dolastane diterpenes

Cited by 104 publications

References 4 publications

[2+2] Photocycloaddition of 3‐Alkenyloxy‐2‐cycloalkenones: Enantioselective Lewis Acid Catalysis and Ring Expansion

[2+2] Photocycloaddition of 3‐Alkenyloxy‐2‐cycloalkenones: Enantioselective Lewis Acid Catalysis and Ring Expansion

A Novel Synthesis of 1-Acetyl-4-Isopropenyl-1-Cyclopentene by Chemoselective Cyclization of 4-Methyl-3-(Oxobutyl)-4-Pentenal: An Important Intermediate for Natural Product Synthesis

Computer-Aided Organic Synthesis – SESAM: A Simple Program to Unravel “Hidden” Restructured Starting Materials Skeleta in Complex Targets

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