Substituted acrylamide derivatives of benzylamine are lithiated α to nitrogen by LDA. The benzyllithium thus formed undergoes either 5-endo-trig anionic cyclisation, formally by intramolecular conjugate addition to the acrylamide, to yield 5-membered lactams, or, if the acrylamide bears a β-electron withdrawing group, 4-exo-trig cyclisation to a β-lactam.
苄胺的
丙烯酰胺衍
生物被
LDA锂化,在氮原子上形成β位。由此形成的苄基
锂发生5-内型三阴离子环化反应,通过分子内共轭加成到
丙烯酰胺上,生成5元内酰胺,或者,如果
丙烯酰胺带有β-电子吸引基团,则发生4-外型
三环化反应,生成β-内酰胺。