设计并合成了四肽,该四肽包含一个终止的伯胺和构象受限的d -Pro-Gly或d -Pro-Aib(2-氨基异丁酸)链段作为强β-转核元素,并通过N-模块二肽与溶液中的C模块二肽。它们首先被用于催化羟醛反应,并被发现是有效的转化催化剂。四肽Val- d -Pro-Gly-Leu-OH(1g)是最佳的有机催化剂。结果表明,在密集的β转角构象,通过CD和NOESY光谱表明,促成了(ř)-丙酮中的丙酮反应具有较高的对映选择性,而急剧变化的构象应有助于1,2-二氯乙烷(DCE)中反应的低对映选择性和(S)产物。羟基丙酮反应中的不对称诱导不受溶剂的影响,在MeCN中添加1克添加剂(S)-BINOL可达到主要的反产物。
Peptide-Catalyzed Highly Asymmetric Cross-Aldol Reaction of Aldehydes to Biomimetically Synthesize 1,4-Dicarbonyls
作者:Zhi-Hong Du、Bao-Xiu Tao、Meng Yuan、Wen-Juan Qin、Yan-Li Xu、Pei Wang、Chao-Shan Da
DOI:10.1021/acs.orglett.0c01407
日期:2020.6.5
beta-Turn tetrapeptides were demonstrated to catalyze asymmetric aldol reaction of alpha-branched aldehydes and acarbonyl aldehydes, i.e. glyoxylates and alpha-ketoaldehydes, to biomimetically synthesize acyclic all-carbon quaternary center-bearing 1,4-dicarbonyls in high yield and excellent enantioselectivity under mild conditions. The spatially restricted environment of the tetrapeptide warrants high enantioselectivity and yield with broad substrates. Using this protocol, (R)-pantolactone, the key intermediate of vitamin BS, was readily accessed in a practical, efficient, and environmentally benign process from inexpensive starting materials.