Enantioselective synthesis of methyl 2-[1-[( tert -butoxycarbonyl)amino]ethyl]-4-methyloxazole-5-carboxylate by a one–pot enamide cyclization
作者:Takuji Magata、Saeka Nagano、Takuya Endo、Jun Kawaida、Shiho Nagaoka、Yoshimi Hirokawa、Naoyoshi Maezaki
DOI:10.1016/j.tetlet.2017.08.003
日期:2017.9
Methyl 2-[1-[(tert-butoxycarbonyl)amino]ethyl]-4-methyloxazole-5-carboxylate (1) was synthesized with high optical purity via a Pd–catalyzed amide coupling with vinyl triflate with subsequent oxazole formation. The latter reaction proceeds via bromination of an enamide with NBS and DBU-promoted cyclization. The oxazole subunit positional isomer in a macrocyclic azole peptide was obtained in a good
2- [1-[(叔丁氧基羰基)氨基]乙基] -4-甲基恶唑-5-羧酸甲酯(1)是通过Pd催化的酰胺与三氟甲磺酸乙烯酯偶联并随后形成恶唑而以高光学纯度合成的。后一反应通过用NBS进行的酰胺溴化和DBU促进的环化来进行。大环唑肽中的恶唑亚基位置异构体以高收率获得,没有外消旋作用。还研究了该反应的范围和局限性。