An all-cis-functionalized cyclopropane template to connect the three peptide chains in a collagen model is designed. Stereoselective synthesis of cyclopropane-assembled collagen-model 2b with the minimum unit of Gly-Pro-Pro is based on a novel 1-seleno-2-silylethene [2 + 1] cycloaddition strategy. Reaction of the 1-seleno-2-silylethene 4 with triester-substituted olefin 5 in the presence of ZnI2 gives [2 + 1] cycloadduct 6 stereoselectively. Cyclopropane 6 is selectively transformed into triol 10 in four steps. The reaction of 10 and three equivalents of N-Boc-Pro-Pro-Gly-OH in the presence of WSC–DMAP and subsequent deprotection with TFA gives 2b.
设计了一种全顺式功能化的
环丙烷模板,用于连接胶原模型中的三条肽链。基于一种新颖的1-
硒-2-
硅乙烯[2 + 1]环加成策略,立体选择性合成了具有最小单元Gly-Pro-Pro的
环丙烷组装胶原模型2b。1-
硒-2-
硅乙烯4与三
酯取代的
烯烃5在ZnI2存在下反应,选择性生成[2 + 1]环加成产物6。
环丙烷6经过四个步骤选择性转化为三醇10。10与三当量N-Boc-Pro-Pro-Gly-OH在WSC–
DMAP的存在下反应,随后用T
FA去保护,得到2b。