Asymmetric Allylation of α-Ketoester-Derived<i>N</i>-Benzoylhydrazones Promoted by Chiral Sulfoxides/<i>N</i>-Oxides Lewis Bases: Highly Enantioselective Synthesis of Quaternary α-Substituted α-Allyl-α-Amino Acids
作者:Gloria Reyes-Rangel、Yamir Bandala、Fred García-Flores、Eusebio Juaristi
DOI:10.1002/chir.22159
日期:2013.9
Chiral sulfoxides/N‐oxides (R)‐1 and (R,R)‐2 are effective chiral promoters in the enantioselective allylation of α‐keto ester N‐benzoylhydrazone derivatives 3a, 3b, 3c, 3d, 3e, 3f, 3g to generate the corresponding N‐benzoylhydrazine derivatives 4a, 4b, 4c, 4d, 4e, 4f, 4g, with enantiomeric excesses as high as 98%. Representative hydrazine derivatives 4a, 4b were subsequently treated with SmI2, and
手性亚砜/ Ñ -oxides([R )- 1和(- [R ,- [R ) - 2是α酮的对映选择性烯丙基酯有效手性启动子Ñ -benzoylhydrazone衍生物3a中,图3b,图3c,3D,3E,3F,3克到生成相应的N-苯甲酰肼衍生物4a,4b,4c,4d,4e,4f,4g,对映体过量高达98%。随后将代表性的肼衍生物4a,4b用SmI 2处理,并将所得的氨基酯5a,5b用LiOH处理,得到季构α-取代的α-烯丙基α-氨基酸6a,6b,其绝对构型指定为(S),化学基础和电子圆二色性(ECD)数据基础。手性25:529–540,2013年。©2013 Wiley Periodicals,Inc.