tetrapeptide units, followed by peptide coupling and macrocyclization. The three oxazole amino acid fragments are readily accessible by rhodium(II)-catalyzed amide N–H insertion of diazocarbonyl compounds, or by the cycloaddition of rhodium carbenoids with nitriles.
环状十二肽wewakazole和wewakazole B通过不同的策略,通过常见的含有tris-脯
氨酸的
恶唑八肽和两个单独的bis-
恶唑的四肽单元合成,然后进行肽偶联和大环化。这三个
恶唑氨基酸片段可通过重氮羰基化合物的
铑(II)催化的酰胺N–H插入,或
铑类化合物与腈的环加成而容易地获得。