Zeolites are the most used catalysts worldwide in petrochemistry processes, with particular ability to stabilizecarbocations. However, the use of zeolites in organicsynthesis is still scarce. We show here that representative carboxonium-mediated organic reactions, such as the Nazarov cyclization and the tert-butylation of alcohols with tert-butyl acetate, typically performed with very strong acid
Convenient preparations of t-butyl esters and ethers from t-butanol
作者:Stephen W. Wright、David L. Hageman、Ann S. Wright、Lester D. McClure
DOI:10.1016/s0040-4039(97)01792-9
日期:1997.10
A one-pot preparation of t-butylesters and ethers is described that proceeds from the carboxylic acid or alcohol and t-butanol using only anhydrous magnesium sulfate and catalytic sulfuric acid as additional reagents. The method affords t-butylesters and ethers in good yields and is applicable to a variety of substrates.
A compound represented by the general formula (I):
wherein R
1
is a hydrogen atom, a halogen atom, or the like; R
2
, R
3
, and R
4
are each independently a hydrogen atom, a halogen atom, C1-C15 alkyl optionally substituted with one or more C1-C12 alkyloxy or the like, or the like; R
5
is a hydrogen atom or the like; R
6
and R
7
are a hydrogen atom or the like; R
8
is C1-C3 alkyl or the like; R
9
is a hydrogen atom or the like), a prodrug, a pharmaceutically acceptable salt, or solvate thereof.
A compound represented by the general formula (I):
wherein R
1
is a hydrogen atom, a halogen atom, or the like; R
2
, R
3
, and R
4
are each independently a hydrogen atom, a halogen atom, C1-C15 alkyl optionally substituted with one or more C1-C12 alkyloxy or the like, or the like; R
5
is a hydrogen atom or the like; R
6
and R
7
are a hydrogen atom or the like; R
8
is C1-C3 alkyl or the like; R
9
is a hydrogen atom or the like), a prodrug, a pharmaceutically acceptable salt, or solvate thereof.
A Simple and Powerful tert-Butylation of Carboxylic Acids and Alcohols
作者:Kosuke Namba、Chie Ogasa、Kimika Kayano
DOI:10.1055/a-2161-9689
日期:2024.1
A simple and safe tert-butylation reaction was developed. Treatment of various free amino acids with 1.1 equivalents of bis(trifluoromethanesulfonyl)imide in tert-butyl acetate directly afforded tert-butyl esters with free amino groups quickly and in good yields. In addition, various carboxylicacids and alcohols without amino groups were converted into tert-butyl esters and ethers, respectively, in