10.1021/jo301563j.s001
Camille Lescot
Camille
Lescot
Benjamin Darses
Benjamin
Darses
Florence Collet
Florence
Collet
Pascal Retailleau
Pascal
Retailleau
Philippe Dauban
Philippe
Dauban
Intermolecular C–H
Amination of Complex Molecules: Insights into the Factors Governing
the Selectivity
American Chemical Society
2016
steric
cyclic substrates
intramolecular addition
combination
regio
bond
enol ethers
Complex Molecules
chiral aminating agent 1
nitrene insertion
amination
stereoselective nitrene transfer
substrate increases
hyperconjugative effects
chemoselectivity
Factors Governing
stoichiometric amounts
2016-02-20 12:28:14
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Intermolecular_C_H_Amination_of_Complex_Molecules_Insights_into_the_Factors_Governing_the_Selectivity/2489440
Transition-metal-catalyzed C–H amination via nitrene
insertion allows the direct transformation of a C–H into a
C–N bond. Given the ubiquity of C–H bonds in organic
compounds, such a process raises the problem of regio- and chemoselectivity,
a challenging goal even more difficult to tackle as the complexity
of the substrate increases. Whereas excellent regiocontrol can be
achieved by the use of an appropriate tether securing intramolecular
addition of the nitrene, the intermolecular C–H amination remains
much less predictable. This study aims at addressing this issue by
capitalizing on an efficient stereoselective nitrene transfer involving
the combination of a chiral aminating agent <b>1</b> with a
chiral rhodium catalyst <b>2</b>. Allylic C–H amination
of terpenes and enol ethers occurs with excellent yields as well as
with high regio-, chemo-, and diastereoselectivity as a result of
the combination of steric and electronic factors. Conjugation of allylic
C–H bonds with the π-bond would explain the chemoselectivity
observed for cyclic substrates. Alkanes used in stoichiometric amounts
are also efficiently functionalized with a net preference for tertiary
equatorial C–H bonds. The selectivity, in this case, can be
rationalized by steric and hyperconjugative effects. This study, therefore,
provides useful information to better predict the site of C–H
amination of complex molecules.