Synthesis of β- and γ-lactam fused dihydropyrazinones from Ugi adducts via a sequential ring construction strategy. Issue 84 (23rd September 2020)

• Record Type: Journal Article
• Authors: Singh, Sangh Priya; Tripathi, Shashank; Yadav, Anamika; Kant, Ruchir; Srivastava, Hemant Kumar; Srivastava, Ajay Kumar
• Is Part Of: Chemical communications. Volume 56:Issue 84(2020)
• Page Start: 12789
• Page End: 12792
• Publication Date: 2020-09-23
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1039/d0cc04415f
• Languages: English
• ISSNs: 1359-7345

Abstract

Abstract : An efficient and novel method for the synthesis of bicyclic lactams is reported via post-Ugi functionalization. Abstract : A modular approach for the construction of β- and γ-lactam fused dihydropyrazinones from the readily available Ugi adducts has been described. The sequential construction of rings through base-mediated cycloisomerization followed by acid-mediated cyclization yielded β-lactam fused dihydropyrazinones. However, the Ugi-derived dihydropyrazinones afforded γ-lactam fused dihydropyrazinones under base-mediated cycloisomerization. The regioselectivity in the cycloisomerization reactions is explained on the basis of ring-strain. Substrate scope, limitations and mechanistic investigations through DFT-calculations have been explored.