ChemInform Abstract: CHEMISTRY OF ENOL ETHERS. LXVIII. SILYL ETHERS OF ENOLS IN MODIFIED ALDOL-CROTONIC CONDENSATION. PREPARATION OF α,β-UNSATURATED KETONES

1984 ◽  
Vol 15 (48) ◽  
Author(s):  
S. M. MAKIN ◽  
R. I. KRUGLIKOVA ◽  
T. K. TAGIROV ◽  
O. V. KHARITONOVA
Keyword(s):  
Enol Ethers ◽  
Silyl Ethers ◽  
Unsaturated Ketones ◽  
Crotonic Condensation

Asymmetric Synthesis of Ethers by Catalytic Alkene Hydro­alkoxy­lation

Synthesis ◽  
2020 ◽  
Vol 52 (15) ◽  
pp. 2127-2146
Author(s):  
Zhi Li ◽  
Wen-Bin Xie
Keyword(s):  
Asymmetric Synthesis ◽  
Carboxylic Acids ◽  
Carbonyl Compounds ◽  
High Reactivity ◽  
Enol Ethers ◽  
Unsaturated Esters ◽  
Unsaturated Ketones ◽  
Recent Developments ◽  
Catalytic Asymmetric

Many chiral ethers have important physiological activities. Although many asymmetric hydroalkoxylations of olefins with alcohols or phenols have been developed to make chiral ethers, challenges still remain in achieving high reactivity and selectivity over an ever-increasing diversity of alkenes and alcohols. In this review, recent developments on catalytic asymmetric alkene hydroalkoxylations are summarized based on the substitution patterns of alkenes.1 Introduction2 Asymmetric Hydroalkoxylation of Non-Activated Alkenes2.1 Intramolecular Additions2.2 Intermolecular Additions3 Asymmetric Hydroalkoxylation of Enol Ethers3.1 Intramolecular Additions3.2 Intermolecular Additions4 Asymmetric Hydroalkoxylation of α,β-Unsaturated Carbonyl Compounds4.1 α,β-Unsaturated Ketones and Aldehydes as Substrates4.2 α,β-Unsaturated Esters, Amides and Carboxylic Acids as Substrates5 Asymmetric Hydroalkoxylation of Allenes5.1 Intramolecular Additions5.2 Intermolecular Additions6 Conclusion

Thermal rearrangement of functionalized 1,2-divinylcyclopropane systems. A convenient synthesis of substituted 4-cyclohepten-1-ones

1986 ◽  
Vol 64 (1) ◽  
pp. 180-187 ◽  
Author(s):  
Edward Piers ◽  
Max S. Burmeister ◽  
Hans-Ulrich Reissig
Keyword(s):  
Acid Hydrolysis ◽  
The Other ◽  
Thermal Rearrangement ◽  
Enol Ethers ◽  
Acyl Chlorides ◽  
Silyl Ethers ◽  
Convenient Synthesis ◽  
Enol Silyl Ethers ◽  
Hydrolysis Of ◽  
Subsequent Acid

Reaction of the acyl chlorides 14–21 with lithium (phenylthio)(cis-2-vinylcyclopropyl)cuprate (2) provided the ketones 22–29. Compounds 22–25, upon treatment with i-Pr2NLi-Me3SiCl, were converted cleanly into the enol silyl ethers 30–33, which gave the 1,4-cycloheptadienes 34–37 upon thermolysis (100–110 °C). Acid hydrolysis of the latter materials produced the corresponding 4-cyclohepten-1-ones 38–41. However, subjection of the cis-2-vinylcyclopropyl ketones 26–29 to i-Pr2NLi-t-BuMe2SiCl afforded, in each case, a mixture of isomeric enol ethers (26 → 42 + 44 (1:1); 27 → 43 + 45 (1:9); 28 → 56 + 58 (1:1); 29 → 57 + 59 (4:1)). Thermolysis (150–175 °C) of these mixtures, followed by acid hydrolysis of the resultant products, gave the 4-cyclohepten-1-ones 54, 55, 64, and 65, admixed with the corresponding 3-methylenecyclopentenes 52, 53, 62, and 63. On the other hand, treatment of the trans-2-vinylcyclopropyl ketones 70–74 with i-Pr2NLi–t-BuMe2SiCl provided exclusively or predominantly the enol ethers 75–79. Thermolysis (230 °C) of the latter materials and subsequent acid hydrolysis of the resultant products 80, 50, 51, 60, and 61 afforded the 4-cyclopenten-1-ones 38, 54, 55, 64, and 65.

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