Electrochemical Decarboxylation Of Carboxylic Acid Esters

Organic electrosynthesis is an important method in synthetic chemistry.Based on its sustainability and high efficiency,this type of method is widely used in the construction of various types of chemical bonds.Compared with the traditional transition metal-catalyzed carbon-carbon bond cleavage process,organic electrosynthesis uses electric current as a cheap,efficient and relatively safe reagent to replace stoichiometric chemical oxidation or reduction reagents.In addition,since the reactivity can be adjusted by changing the applied electrochemical parameters and conditions(such as electric potential,current,or supporting electrolyte),electrochemical carbon-carbon bond cleavage can be selectively achieved.Organoboron compounds are a class of useful reagents widely used in organic synthetic chemistry,and are widely used in the Suzuki-Miyaura coupling reaction and the conversion process of many other functional groups.As an important part of it,alkyl boron compounds play an important role in medicinal chemistry and synthetic chemistry.However,the previous synthetic methods of alkyl boron compounds have corresponding limitations.The requirements for substrate structure and the lack of compatibility of functional groups have greatly restricted the practicability of these methods.In this context,we have developed an electrochemically promoted method for decarboxylation of alkyl carboxylates.The corresponding alkyl carboxylic acid ester is prepared by reacting the alkyl carboxylic acid with N-hydroxyphthalimide,and then the alkyl boronic acid ester is generated with the boron reagent under constant current electrolysis conditions.The reaction system is simple and does not require any metal catalysts or additional redox agents.Under the optimal reaction conditions,35 alkyl borate products have been expanded,with a yield of 31%-80%.The types of substrates include primary and secondary,tertiary alkyl carboxylic acid esters and a variety of β,γ-amino acids,It is also compatible with several drug molecules that are widely used clinically(such as antiepileptic drugs pregabalin,gabapentin,etc.),and the corresponding borate products can be obtained with a yield of 43%-53%.In addition,we also achieved the "one-pot" and scale-up reaction,and also obtained the desired target product with a yield of 48%,fully demonstrating the application potential of this method.