New Preorganized γ-Amino Acids as Foldamer Building Blocks
作者:Li Guo、Weicheng Zhang、Ilia A. Guzei、Lara C. Spencer、Samuel H. Gellman
DOI:10.1021/ol3008815
日期:2012.5.18
An asymmetric synthesis of two new diastereomeric γ-amino acids is described. Both molecules contain a cyclohexyl ring to limit conformational flexibility about the Cα–Cβ bond; they differ in having cis vs trans stereochemistry on the ring. Residues derived from the cis γ isomer are shown to support helical secondary structures in α/γ-peptide oligomers.
描述了两种新的非对映体 γ-氨基酸的不对称合成。两个分子都包含一个环己基环以限制 C α -C β键的构象灵活性;它们的不同之处在于环上的顺式与反式立体化学。来自顺式γ 异构体的残基显示支持 α/γ-肽寡聚体中的螺旋二级结构。
[EN] GAMMA AMINO ACID BUILDING BLOCKS<br/>[FR] ÉLÉMENTS CONSTITUTIFS DE GAMMA-AMINOACIDES
申请人:WISCONSIN ALUMNI RES FOUND
公开号:WO2011047190A1
公开(公告)日:2011-04-21
The invention provides compounds and methods, for example, to carry out organocatalytic Michael additions of aldehydes to cyclically constrained nitroethylene compounds catalyzed by a pro line derivative to provide cyclically constrained α-substituted-γ-nitro-aldehydes. The reaction can be rendered enantioselective when a chiral pyrrolidine catalyst is used, allowing for Michael adducts in nearly optically pure form (e.g., 96 to >99% e.e.). The Michael adducts can bear a single substituent or dual substituents adjacent to the carbonyl. The Michael adducts can be efficiently converted to cyclically constrained protected γ- amino acid residues, which are essential for systematic conformational studies of γ-peptide foldamers. New methods are also provided to prepare other γ-amino acids and peptides. These new building blocks can be used to prepare foldamers, such as α/γ-peptide foldamers, that adopt specific helical conformations in solution and in the solid state.
The invention provides compounds and methods, for example, to carry out organocatalytic Michael additions of aldehydes to cyclically constrained nitroethylene compounds catalyzed by a proline derivative to provide cyclically constrained α-substituted-γ-nitro-aldehydes. The reaction can be rendered enantioselective when a chiral pyrrolidine catalyst is used, allowing for Michael adducts in nearly optically pure form (e.g., 96 to >99% e.e.).
The Michael adducts can bear a single substituent or dual substituents adjacent to the carbonyl. The Michael adducts can be efficiently converted to cyclically constrained protected γ-amino acid residues, which are essential for systematic conformational studies of γ-peptide foldamers. New methods are also provided to prepare other γ-amino acids and peptides. These new building blocks can be used to prepare foldamers, such as α/γ-peptide foldamers, that adopt specific helical conformations in solution and in the solid state.