β-内酰胺环与青霉素、头孢菌素、诺卡霉素和硫霉素等抗生素的生理活性有密切关系。对于β-内酰胺化合物的合成已进行了很多研究,但到目前为止,将β-内酰胺作为有意义的合成中间体的研究尚未引起注意。为了将β-内酰胺作为中间体,就有必要巧妙地利用其选择性开环反应。β-内酰胺有a、b、c、d等开环方式和二种[2+2]复分解反应(式1)。按a式开环,则水解成β-氨基酸。按b式开环,保留了酰胺结构。4位有芳基的β-内酰胺用Pd催化,容易按b式使N—C~4键还原开裂。对b式的开裂,苄基的位置是关键。N-苄 The β-lactam ring is closely related to the physiological activities of antibiotics such as penicillin, cephalosporin, nocicecin and thiophanmycin. Numerous studies have been conducted on the synthesis of β-lactam compounds, but so far no studies have been made on the study of β-lactam as a meaningful synthetic intermediate. In order to use β-lactam as an intermediate, it is necessary to make clever use of its selective ring-opening reaction. β-lactams have a, b, c, d open loop and two [2 + 2] metathesis reactions (Equation 1). Press a ring, then hydrolyzed into β-amino acids. Open by ring b, retaining the amide structure. The 4-position β-lactam with Pd is catalyzed by Pd, and the N-C ~ 4 bond is easily reduced and cleaved by the formula b. For b-cleavage, the position of the benzyl group is the key. N-benzyl