esters is demonstrated. This protocol efficiently installs various tertiary or secondary alkyl fragments onto the nitrogen atom of azole nucleophiles undermild and transition-metal-free conditions. The pyridinium additive successfully inhibits the formation of elimination byproducts from the carbocation intermediate. This reaction is applicable to the synthesis of a protein-degrader-like molecule
Electrochemical Decarboxylative <i>N</i>-Alkylation of Heterocycles
作者:Tao Sheng、Hai-Jun Zhang、Ming Shang、Chi He、Julien. C. Vantourout、Phil. S. Baran
DOI:10.1021/acs.orglett.0c02799
日期:2020.10.2
An operationally simple method to employ nonactivated carboxylic acids as alkylating agents in the N-alkylation of heterocycles is reported through an electrochemically driven anodic decarboxylative process. A wide substrate scope across a range of heterocycles is demonstrated along with a series of applications that significantly reduce the step count required to access such medicinally relevant structures
The reaction of the 5-unsubstituted pyrazoles 2a-k with lithium diisopropylamide or n-butyllithium gave intermediary 5-lithiopyrazoles, whose reaction with sulfur dioxide afforded the lithium pyrazole-5-sulfinates 3a-k. Subsequent reaction of 3a-k with N-chlorosuccinimide followed by ammonolysis provided the pyrazole-5-sulfonamides 5a-k.