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.