Enantioconvergent Arylation of Racemic Secondary Alcohols to Chiral Tertiary Alcohols Enabled by Nickel/N-Heterocyclic Carbene Catalysis

2021 ◽  
Author(s):  
Yuan Cai ◽  
Shi-Liang Shi
Keyword(s):  
Secondary Alcohols ◽  
Tertiary Alcohols ◽  
Chiral Tertiary Alcohols

Asymmetric Synthesis of Chiral Tertiary Alcohols in High Enantiomeric Excess

1982 ◽  
pp. 37-53 ◽  
Author(s):  
ERNEST L. ELIEL ◽  
JORMA K. KOSKIMIES ◽  
BRUNO LOHRI ◽  
W. JACK FRAZEE ◽  
SUSAN MORRIS-NATSCHKE ◽  
...  
Keyword(s):  
Asymmetric Synthesis ◽  
Enantiomeric Excess ◽  
Tertiary Alcohols ◽  
Chiral Tertiary Alcohols

Polymer-Support Synthesis of Chiral Tertiary Alcohols

Synfacts ◽  
2006 ◽  
Vol 2006 (11) ◽  
pp. 1181-1181
Author(s):  
D. Ramón ◽  
M. Yus ◽  
V. Forrat
Keyword(s):  
Polymer Support ◽  
Tertiary Alcohols ◽  
Chiral Tertiary Alcohols

scholarly journals Asymmetric Synthesis of Tertiary α -Hydroxyketones by Enantioselective Decarboxylative Chlorination and Subsequent Nucleophilic Substitution

Molecules ◽  
2020 ◽  
Vol 25 (17) ◽  
pp. 3902
Author(s):  
Mei Kee Kam ◽  
Akira Sugiyama ◽  
Ryouta Kawanishi ◽  
Kazutaka Shibatomi
Keyword(s):  
Asymmetric Synthesis ◽  
Nucleophilic Substitution ◽  
Primary Amine ◽  
Tetrabutylammonium Hydroxide ◽  
Tertiary Alcohols ◽  
Tertiary Carbon ◽  
Chiral Tertiary Alcohols

Chiral tertiary α-hydroxyketones were synthesized with high enantiopurity by asymmetric decarboxylative chlorination and subsequent nucleophilic substitution. We recently reported the asymmetric decarboxylative chlorination of β-ketocarboxylic acids in the presence of a chiral primary amine catalyst to obtain α-chloroketones with high enantiopurity. Here, we found that nucleophilic substitution of the resulting α-chloroketones with tetrabutylammonium hydroxide yielded the corresponding α-hydroxyketones without loss of enantiopurity. The reaction proceeded smoothly even at a tertiary carbon. The proposed method would be useful for the preparation of chiral tertiary alcohols.

Studies on the Immobilized-Lipase-Catalyzed Esterification of Alkyl Oleates in Solvent-Free Systems

2013 ◽  
Vol 645 ◽  
pp. 19-23 ◽  
Author(s):  
Hui Zhong ◽  
Zheng Fang ◽  
Bao Hua Zou ◽  
Xin Li ◽  
Kai Guo
Keyword(s):  
Oleic Acid ◽  
Low Temperature ◽  
High Selectivity ◽  
Immobilized Lipase ◽  
Enzyme Concentration ◽  
Molar Ratio ◽  
High Yield ◽  
Secondary Alcohols ◽  
Tertiary Alcohols ◽  
Candida Sp

The esterification of oleic acid with alkyl alcohols in solv ent-free systems was catalyzed by an immobilized lipase from Candida sp . 99-125. The influence of several factors, including enzyme concentration, temperature, molar ratio between oleic acid and alkyl alcohols, and structure of alcohol was also investigated. The results indicated that the reactions catalyzed by lipase at 20 o C, in the presence of 3% (w/w) lipase, on the molar ratio of 1:1 between oleic acid and alcohols, afforded products in high yield. It showed high selectivity to primary and low selectivity to secondary alcohols and tertiary alcohols because of the sterically hindered effect. Methanol has certain toxicity on the activity of the lipase. The lipase from Candida sp. 99-125 was identified to be an effective catalyst in the esterification of alcohol and oleic acid at low temperature.

Chromic acid oxidation of aromatic alcohols

1969 ◽  
Vol 47 (17) ◽  
pp. 3207-3212 ◽  
Author(s):  
Ross Stewart ◽  
Fariza Banoo
Keyword(s):  
Chromic Acid ◽  
Acid Oxidation ◽  
Secondary Alcohols ◽  
Tertiary Alcohols ◽  
Chromic Acid Oxidation ◽  
Hydride Shift ◽  
Rate Of Reaction ◽  
Aromatic Alcohols ◽  
Reaction Constant ◽  
Rate Controlling Step

The mechanism of the chromic acid oxidation of di- and tri-aryl carbinols has been studied in 80 wt% acetic acid containing sulfuric acid. The reactions are cleanly second-order and give benzophenones in the case of the secondary alcohols and benzophenones plus phenols in the case of the tertiary alcohols. Electron-donating substituents in the tertiary alcohol appear predominantly in the phenol component and the rate-controlling step is believed to be a 1,2-aryl shift. The reaction constant for the migration is ρ+ = −1.44 and that for the overall reaction is ρ+ = −0.879. The presence of manganous ions does not alter these values although it lowers the overall rate of reaction. Although an analogous 1,2-hydride shift mechanism can be written for the oxidation of the secondary alcohols, there are enough points of difference between the oxidations of the secondary and tertiary systems to make this appear unlikely.

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