Mild, efficient and racemization-free synthesis of N-protected α, β-unsaturated γ-amino esters with unprecedented high E- stereoselectivity is described. This method is found to be compatible with Boc-, Fmoc- and other side chain protecting groups. The crystal conformations of the vinylogous γ-amino esters in monomers and in homo- and mixed dipeptides are studied. Further, the vinylogous homo-dipeptide showed a β-sheet conformation, while mixed α- and α,β-unsaturated γ-hybrid dipeptide adapted an irregular structure in single crystals.
描述了一种温和、高效且无光学异构化的N保护α, β-不饱和γ-
氨基酯的合成方法,该方法具有前所未有的高E型立体选择性。该方法与Boc、Fmoc及其他侧链保护基团相容。研究了单体和同源及混合二肽中
乙烯基γ-
氨基酯的晶体构象。此外,
乙烯基同源二肽显示出β-折叠构象,而混合的α型和α,β-不饱和γ-杂合二肽在单晶中适应了不规则结构。