Construction of quaternary carbon centers by KOtBu-catalyzed α-homoallylic alkylation of lactams with 1,3-dienes

We report a KOtBu-catalyzed alpha-homoallylic alkylation of lactams with 1,3-dienes. With this transition metal-free and atom-economical protocol, a variety of alpha-homoallylic alkylated lactams bearing alpha-quaternary carbon centers were formed in a 2,1-addition manner with excellent regioselectivity. A cation-pi interaction between the in situ-generated potassium enolate and the diene is proposed to play a key role in accelerating this transformation.

Automated summary

A KOtBu-catalyzed alpha-homoallylic alkylation of lactams with 1,3-dienes is reported in this study. This transition metal-free and atom-economical protocol allows for the formation of alpha-homoallylic alkylated lactams bearing alpha-quaternary carbon centers with excellent regioselectivity. A proposed cation-pi interaction between the in situ-generated potassium enolate and the diene plays a key role in accelerating this transformation.