Chan‐Lam Coupling: Synthesis of N‐alkylated Derivatives of ϵ‐Caprolactams from Bicyclic Amidine DBU

The reactivity of bicyclic amidine 1,8‐diazabicyclo[5.4.0]undec‐8‐ene (DBU) with phenyl boronic acid forming N‐alkylated derivatives represents an advanced example to the existing classical Chan‐Lam Cross Coupling of amines. The conversion of DBU to important heterocyclic scaffolds, in which DBU is acting as a nucleophile forming N‐alkylated derivatives of ϵ‐caprolactam is described. This copper‐catalyzed reaction of DBU with phenylboronic acids represents a new paradigm of Chan‐Lam amination. This type of transformation has opened up a new direction for the synthesis of 1‐(3(phenyl amino) propyl)azepan‐2‐ones directly from the diimide, DBU in a single synthetic operation. The reaction was compatible with bicyclic amidines, 1,5‐diazabicyclo‐[4.3.0]non‐5‐ene (DBN) and 1,5,7 triazabicyclo[4.4.0]dec‐5‐ene (TBD), providing a robust system to access valuable bioactive ϵ‐caprolactams. A new paradigm of Chan‐Lam amination! The copper‐catalyzed transformation has opened up a new direction for the synthesis of 1‐(3(phenyl amino) propyl)azepan‐2‐ones directly from the diimide, DBU and phenylboronic acids in a single synthetic operation. The reaction is compatible with bicyclic amidines, 1,5‐diazabicyclo‐[4.3.0]non‐5‐ene (DBN) and 1,5,7 triazabicyclo[4.4.0]dec‐5‐ene (TBD), providing a robust system to access valuable bioactive ϵ‐caprolactams.