2 research outputs found
Metal-Free Intermolecular Coupling of Arenes with Secondary Amides: Chemoselective Synthesis of Aromatic Ketimines and Ketones, and <i>N</i>‑Deacylation of Secondary Amides
The direct transformation of common
secondary amides into aromatic
ketimines and aromatic ketones with C–C bond formation is described.
The reaction can also be used for <i>N</i>-deacylation of
secondary amides to release amines. This method consists of <i>in situ</i> amide activation with triflic anhydride and intermolecular
capture of the resulting highly electrophilic nitrilium intermediate
with an arene. The reaction is applicable to various kinds of secondary
amides (electrophiles), but only electron-rich and moderately electron-rich
arenes can be used as nucleophiles. Thanks to the use of bench stable
arenes instead of reactive and basic organometallics as nucleophiles,
the reaction proceeded with high chemoselectivity at the secondary
amido group in the presence of a series of sensitive functional groups
such as aldehyde, ketone, ester, cyano, nitro, and tertiary amido
groups. The reaction can be viewed as a Friedel–Crafts-type
reaction using secondary amides as acylating agents or as an intermolecular
version of the Bischler–Napieralski reaction
A General Method for the One-Pot Reductive Functionalization of Secondary Amides
A one-pot
reaction for the transformation of common secondary amides
into amines with C–C bond formation is described. This method
consists of <i>in situ</i> amide activation with Tf<sub>2</sub>O–partial reduction–addition of <i>C</i>-nucleophiles. The method is general in scope, which allows employing
both hard nucleophiles (RMgX, RLi) and soft nucleophiles, as well
as enolates. With the use of soft nucleophiles, the reaction proceeded
with high chemoselectivity at a secondary amide in the presence of
ester, cyano, nitro, and tertiary amide groups