DBU‐Catalyzed Glutamation of Phenols, Thiophenols, Secondary Amines and Imides

• Published in: European journal of organic chemistry 2024-06, Vol.27 (22), p.n/a
• Main Authors: Wang, Xue‐Ying, Zhu, Si‐Kai, Cheng, Mei‐Ling, Jiang, Ru, Zhang, Sheng‐Yong, Wang, Ping‐An
• Format: Article
• Language: English
• Subjects: Amines; base catalysis; Chemical reactions; Esters; Glutamic acid; glutamic acids; Glycine; Imides; Imines; lactamization; Michael addition; Phenols; Room temperature; Thiophenol; unsaturated esters
• ISSN: 1434-193X; 1099-0690
• DOI: 10.1002/ejoc.202400184

1,8‐Diazabicyclo[5.4.0]undec‐7‐ene (DBU) catalyzed Michael addition reactions between α,β‐unsaturated esters and benzophenone‐imines of glycine esters have been realized in THF at room temperature by using LiBr as an additive, effectively enabling the glutamation of phenols, thiophenols, secondary amines and imides. 3‐Substituted glutamic acid esters were obtained in excellent yields and diastereoselectivities (up to quantitative yield and >20 : 1 dr). These glutamic acid esters were readily converted into their corresponding pyroglutamic acid esters in high yields through acidic hydrolysis followed by lactamization. An organic‐superbase‐catalyzed glutamation of phenols, thiophenols, secondary amines and imides has been realized through Michael addition between α,β‐unsaturated esters and benzophenone‐imines of glycine esters. 3‐Substituted glutamic acid esters were obtained in excellent yields and diastereoselectivities (up to quantitative yield and >20 : 1 dr) in THF by using LiBr as an additive at room temperature.