Dearomative [2,3] sigmatropic rearrangement of ammonium ylides followed by 1,4-elimination to form α-(<i>ortho</i>-vinylphenyl)amino acid esters
作者:Eiji Tayama、Sho Sotome
DOI:10.1039/c8ob01091a
日期:——
base-induced dearomative [2,3] sigmatropic rearrangement of amino acid ester-derived ammonium salts followed by 1,4-elimination produced α-(ortho-vinylphenyl)amino acid esters. The reaction of azetidine-2-carboxylic acid-derived ammonium salt, (1S,2S,1′R)-3b, proceeded with a perfect N-to-C chirality transfer to afford α-(ortho-vinylphenyl)azetidine-2-carboxylic acid ester, (R)-5 (99% ee). On the other hand
碱诱导的氨基酸酯衍生的铵盐的脱芳香性[2,3]σ重排,然后进行1,4-消除,生成α-(邻-乙烯基苯基)氨基酸酯。氮杂环丁烷-2-羧酸衍生的铵盐的反应,(1级小号,2小号,1' - [R )- 3b中,具有完美的N对-C手性转移,得到进行α-(邻-vinylphenyl)氮杂环丁烷2-羧酸酯,(R)-5(99%ee)。另一方面,甘氨酸衍生的铵盐(R)-6a的反应,其涉及从手性苄基碳的高效手性转移到酯羰基给出的光学活性α-(的α -碳邻-vinylphenyl)甘氨酸酯,(- [R )- 8a中(85%ee)的,被证明。尽管先进行脱芳香性的[2,3]重排再进行1,4-消除在底物结构方面有局限性,但我们的方法为获得取代的α-芳基氨基酸衍生物提供了独特的途径。