Uracil bearing a tethered allyl alcohol appendage at N1 undergoes a [2+2] photocycloaddition reaction to provide a single tricyclic adduct in high yield. This compound is transformed in one step into a cis-cyclobutane β-amino acid bearing a 3-hydroxymethyl group. Through appropriate functionalization and epimerization, the trans isomer is obtained therefrom in only three further steps.
在N1处带有拴系的
烯丙醇附属物的尿
嘧啶会进行[2 + 2]光环加成反应,从而以高收率提供单个
三环加合物。将该化合物一步转化为带有3-羟甲基的顺式-
环丁烷β-
氨基酸。通过适当的官能化和差向异构化,仅三个另外的步骤就可以由此获得反式异构体。