Enantioselective Entry to theHomalium Alkaloid Hoprominol: Synthesis of an (R,R,R)-Hoprominol Derivative
作者:Corinne Ensch、Manfred Hesse
DOI:10.1002/hlca.200390016
日期:2003.1
the chiral β-amino acid portions 10a and 10b, respectively, by application of a set of reactions (e.g., N-alkylation of 10a,b and Sb(OEt)3-assisted cyclization of the resulting open-chain intermediates) already known. In comparison with the total syntheses of homaline (1) and homoprine (2), the newness of the described synthesis lies in the asymmetric approach to the difunctionalized fatty acid derivative
描述了N-和O-保护的hoprominol衍生物(R,R,R)-6的非对映选择性合成。通过环化制备两个基本手性氮杂内酰胺单元7a和7b并随后通过已知方法进行它们的迭代连接,成功构建了双环O-甲硅烷基化和二(N-甲苯磺酰基化)不对称支架6(方案5)。由手性β制备4-烷基-六氢-1,5-重氮星-2(1 H)-酮7a和7b。α-氨基酸部分10A和10B分别,由一组反应(应用例如,N的烷基化10A,b和Sb(OET)3已经知道所得到的开链中间体的环化-assisted)。与homaline(1)和homoprine(2)的总合成相比,所述合成的新颖之处在于从(-)-(S)-苹果酸(9)开始的双官能化脂肪酸衍生物10b的不对称方法。(方案3和4)。制备10b的关键步骤是光学纯的非对映胺化α,β不饱和δ -羟基高烯丙基酯14经由共轭分子内氮杂迈克尔非环的环化δ - (氨基甲酰氧基)中间体11。