Reductive coupling of aliphatic cyclic imides and ω-amidoesters with benzophenones by low-valent titanium: Synthesis of 5-diarylmethylene-1,5-dihydropyrrol-2-ones, 6-diarylmethyl-2-pyridones, and ω-(diarylmethylene)lactams

Abstract

The reductive coupling of cyclic imides and ω-amidoesters with benzophenones by Zn-TiCl4 in THF and subsequent acid-catalyzed dehydration gave 5-diarylmethylene-1,5-dihydropyrrol-2-ones A, 6-diarylmethyl-2-pyridones B, and ω-(diarylmethylene)lactams C. In a similar manner, 3-((benzyloxy)carbonyl)amino substituted A, B, and C were synthesized from the corresponding 3-((benzyloxy)carbonyl)amino cyclic imides and ω-((benzyloxy)carbonyl)amino-ω-amidoesters prepared from L-aspartic and L-glutamic acids. In addition, 4- and 5-((benzyloxy)carbonyl)amino substituted C were also obtained by the same procedures from 2-((benzyloxy)carbonyl)amino-ω-amidoesters prepared from L-asparagine and L-glutamine, respectively.