Régiosélectivité et stéréosélectivité de l'hydroxylation homolytique des hydrocarbures par le peracide benzoïque

1985 ◽  
Vol 63 (3) ◽  
pp. 678-680 ◽  
Author(s):  
Jacques Fossey ◽  
Daniel Lefort ◽  
Massoud Massoudi ◽  
Jean-Yves Nedelec ◽  
Jeanine Sorba
Keyword(s):  
Radical Process ◽  
Tertiary Alcohols ◽  
Perbenzoic Acid ◽  
Cis And Trans

Cyclohexane, methylcyclohexane, and adamantane are hydroxylated by a radical process using perbenzoic acid. A regioselectivity of 60–90% in favour of tertiary alcohols is noted. In the case of cis and trans decalins, stereoselection leading to 9-decalols can reach 97%. Such a stereoselectivity for hydroxylation by use of a peracid does not necessarily indicate lack of a radical pathway.

SYNTHESES IN THE TERPENE SERIES: VIII. SYNTHESIS OF THE CIS- AND TRANS-ISOMERS OF 7,7,10-TRIMETHYLDECAL-1-ONE. A CONVENIENT MODIFICATION OF THE BROWN HYDRATION REACTION

1959 ◽  
Vol 37 (11) ◽  
pp. 1870-1880 ◽  
Author(s):  
Franz Sondheimer ◽  
Saul Wolfe
Keyword(s):  
Trans Isomer ◽  
Raney Nickel ◽  
Equilibrium Mixture ◽  
Hydration Reaction ◽  
Trans Isomers ◽  
Perbenzoic Acid ◽  
Cis And Trans Isomers ◽  
Cis And Trans

7,7,10-Trimethyl-Δ1(9)-octal-2-one (VII) was converted to the cycloethylenedithioketal (VIII), which on Raney nickel reduction yielded 7,7,10-trimethyl-Δ1(9)-octalin (IX). Oxidation with perbenzoic acid led to the corresponding oxide (X), which could be rearranged in low yield to an equilibrium mixture of 7,7,10-trimethyldecal-1-one consisting essentially of the trans-isomer (XI).A convenient modification of the Brown hydration reaction is described, whereby the necessity of generating diborane or of using diglyme is avoided. 7,7,10-Trimethyl-Δ1(9)-octalin (IX) on Brown hydration using this modification stereospecifically furnished 7,7,10β-tri-methyl-cis-decal-1β-ol (XII), which was oxidized to 7,7,10-trimethyl-cis-decal-1-one (XIII). Isomerization resulted in the above-described equilibrium mixture containing at least 90% of the trans-isomer (XI). Similarly, the previously described 10-methyl-Δ1(9)-octalin (XVI) yielded a mixture of the cis- and trans-isomers of 10-methyldecal-1-one (XIX). Syntheses of 2-methylene-7,7,10-trimethyl-Δ1(9)-octalin (XIV) and of 7,7,10-trimethyl-cis-decal-2,3-dione 3-dithiotrimethylene ketal (XXII) are also described.

Nitrones and oxazirans. III. Photolysis of 1-pyrroline 1-oxides and their related oxazirans

1968 ◽  
Vol 21 (10) ◽  
pp. 2507 ◽  
Author(s):  
JB Bapat ◽  
DS Black
Keyword(s):  
Trans Isomer ◽  
Trans Isomers ◽  
Perbenzoic Acid ◽  
Stereo Selectivity ◽  
Cis And Trans

Oxazirans have been prepared from a number of 1-pyrroline 1-oxides by photoisomerization and from the related 1-pyrrolines by oxidation with perbenzoic acid. This oxidation was found to be highly stereoselective in reaction with unsymmetrical pyrrolines, and 3,5-cis-disubstituted oxazirans were formed exclusively. A mixture of 3,5-cis- and trans-disubstituted oxazirans was formed in the photolysis of unsymmetrical 2-methyl-substituted pyrroline 1-oxides but stereo-selectivity was observed in the photolysis of similar 2-aryl-substituted pyrroline 1-oxides, in which cases only the trans-isomer was obtained. Photoisomerization of cis-5-phenyl-substituted oxazirans to their trans-isomers was also observed, while other oxazirans were found to be photo-stable.

Liquid-phase oxidation of 2-butene in the presence of benzaldehyde

1969 ◽  
Vol 47 (17) ◽  
pp. 3191-3197 ◽  
Author(s):  
Fujio Tsuchiya ◽  
Tsuneo Ikawa
Keyword(s):  
Reaction Time ◽  
Liquid Phase ◽  
Co Oxidation ◽  
Experimental Results ◽  
The Other ◽  
Liquid Phase Oxidation ◽  
Perbenzoic Acid ◽  
Phase Oxidation ◽  
Cis And Trans ◽  
Epoxide Formation

The co-oxidation of cis- and trans-2-butene and benzaldehyde at 110 °C has been carried out in benzene and the mechanism of epoxide formation has been investigated by examining the ratio of cis- to trans-epoxides. The results indicate that epoxides were formed by two mechanisms, one involving the benzoylperoxy radical to give about half cis and half trans epoxides and the other by stereospecific epoxidation with perbenzoic acid. Experimental results show that the stereospecific character of epoxidation increases with the reaction time and the concentration of benzaldehyde, but does not depend on the concentration of 2-butene.

Trypanocidal Structure-Activity Relationshipfor Cis- and Trans-methylpluviatolide

Planta Medica ◽  
2008 ◽  
Vol 74 (03) ◽  
Author(s):  
R Silva ◽  
J Saraiva ◽  
S Albuquerque ◽  
C Curti ◽  
PM Donate ◽  
...  
Keyword(s):  
Structure Activity ◽  
Cis And Trans

A Short Synthesis of (+)-Brefeldin C via Enantioselective Radical Hydroalkynylation

2019 ◽  
Author(s):  
Lars Gnägi ◽  
Severin Vital Martz ◽  
Daniel Meyer ◽  
Robin Marc Schärer ◽  
Philippe Renaud
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Oxidation State ◽  
Single Step ◽  
Radical Process ◽  
Target Molecule ◽  
Short Synthesis ◽  
The One

<div><div><div><div><p>A very concise total synthesis of (+)-brefeldin C starting from 2-furanylcyclopentene is described. This approach is based on an unprecedented enantioselective radical hydroalkynylation process to introduce the two cyclopentane stereocenters in a single step. The use of a furan substituent allows to achieve a high trans diastereoselectivity during the radical process and it contains the four carbon atoms C1–C4 of the natural product in an oxidation state closely related to the one of the target molecule. The eight-step synthesis require six product purifications and it provides (+)-brefeldin C in 18% overall yield.</p></div></div></div></div>

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