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Theoretical investigation of von Braun and von Braun‐like reactions
Author(s) -
Couty François,
Burov Oleg N.,
Kletskii Mikhail E.,
Lisovin Anton V.,
Wright Karen,
Drouillat Bruno,
Kurbatov Sergey V.
Publication year - 2020
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.26088
Subject(s) - chemistry , bromine , alkyl , bromide , selectivity , adduct , bond cleavage , cyanogen bromide , medicinal chemistry , reaction mechanism , computational chemistry , organic chemistry , catalysis , biochemistry , peptide sequence , gene
The von Braun reaction, discovered at the dawn of the past century, consists of the reaction between a tertiary amine and cyanogen bromide. It leads to the cleavage of a C─N bond with the formation of an N ‐dialkylcyanamide and an alkyl bromide and has been extensively used in organic synthesis. A detailed in silico study (PCM/density functional theory [DFT]/B3LYP/6‐31++G(d,p) calculations) of this venerable reaction has shown that in the first stage a zwitterionic adduct with a multibonded bromine atom is formed. The widely accepted mechanism involving an S N 2 reaction occurs in the second step, thus accounting for its selectivity. Quantum chemical calculations were performed for the von Braun‐like reactions in systems formed by cyclic tertiary amines ( N ‐alkyl azetidines). In these cases, the first stage is almost the same as in the classical von Braun processes, and selective S N 2 mechanisms can occur in the second step.