Potassium tert-butoxide

Main purpose

1. As a strong base, it is widely used in the condensation, rearrangement and ring opening reactions in chemical, pharmaceutical, pesticide and other organic synthesis. It is also used for printing and dyeing, catalyst, etc. 2. It is a kind of alkali with moderate strength commonly used in organic synthesis. Its alkalinity is stronger than alkali metal hydroxide and alkali metal primary and secondary alkoxide; Weaker than amino-alkali metals and their alkyl derivatives. The reason why t-BuOK is widely used is that it is cheap and easy to obtain, and its alkalinity changes with the selected reaction solvent. The t-BuOH solution of alkylated t-BuOK can effectively carbonyl α- The alkylation reaction at position. T-BuOH solution or benzene solution of t-BuOK is also often used α,β- Alkylation of bisubstituted aldehydes. α,β- Unsaturated ketones can be obtained by treating with excessive t-BuOK/t-BuOH and alkylation reagent α,β- The product of dialkylation. The amount of catalyst t-BuOK can catalyze the addition of ketone or imine with styrene in DMSO to obtain a high yield alkylation product (Formula 1) [1]. Compared with intermolecular reaction, t-BuOK can catalyze intramolecular alkylation in different solvents. α,β- The intramolecular alkylation of unsaturated ketones can be carried out in α-, α 2 - or γ- It depends on the characteristics of the base, the leaving group and other structural characteristics (Formula 2) [2]. Condensation reaction t-BuOK is the most commonly used base for Darzens condensation reaction. Darzens condensation is α- Formation of halogenated esters with ketones and aromatic aldehydes α,β- Reaction of epoxy or glycidyl ester (Formula 3) [3]. Dieckmann cyclization of diesters and their related reactions are widely used in the synthesis of five, six, seven and larger rings [4]. In the asymmetric system, the regioselectivity of the reaction is determined by the spatial effect and the stability of the product enolate. The properties of base can also significantly affect the regioselectivity of this reaction. For Stobbe condensation, t-BuOK is a better base than EtONa, with higher reaction yield, shorter reaction time, and no side reaction of ketone or aldehyde reduction. The mixed reagent formed by Ti (O-n-Bu) 4 and t-BuOK at 1:1 ratio can effectively catalyze the self-condensation of aldehydes, but the stereoselectivity is not high (Formula 4) [5]. Oxacyclic nitriles can be synthesized by ω- (Formula 5) [6] is obtained by condensation reaction of halonitrile under the action of t-BuOK. Eliminate reaction t-BuOK α- Eliminate or β- Elimination has a wide range of applications. It is the most effective base (formula 6) [7] for the traditional alkoxyl-haloform reaction to generate dihalogenated carbenes. When the substrate contains alkyl chloride, bromine, toluenesulfonate, sulfite and other leaving groups, it can be carried out under the action of t-BuOH or t-BuOK in other non-polar solvents β- The reaction can also be carried out in the solid phase. The isomerization of unsaturated compounds t-BuOK can make the alkene and alkyne double bonds migrate through the anion intermediate (formula 7) [8]. Michael addition t-BuOK can also be used as a base in Michael addition reaction. Michael addition products of asymmetric ketones (such as 2-methylcyclohexanone) are mainly in the presence of more substituents α- On the carbon atom. Under the action of t-BuOK, 1,2-prodienone can undergo Michael addition reaction with 1,3-dicarbonyl compounds, with high yield (formula 8) [9]. The rearrangement reaction is a mono-p-toluene sulfonated derivative of cis-1,2-diol, such as α- Pinene derivatives undergo Pinacol rearrangement process under the action of t-BuOK. The trans isomer is converted into epoxide (formula 9) [10] under the same conditions. α- Ramberg-Backlund rearrangement of halogenated sulfones can also be catalyzed by t-BuOK.

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