Contra-thermodynamic E → Z isomerization of cinnamamides via selective energy transfer catalysis
作者:Marc R. Becker、Tobias Morack、Jack Robertson、Jan B. Metternich、Christian Mück-Lichtenfeld、Constantin Daniliuc、Glenn A. Burley、Ryan Gilmour
DOI:10.1016/j.tet.2020.131198
日期:2020.12
A bio-inspired, photocatalytic E → Z isomerization of cinnamides is reported using inexpensive (−)-riboflavin (vitamin B2) under irradiation at λ = 402 nm. This operationally simple transformation is compatible with a range of amide derivatives including –NR2, –NHSO2R and N(Boc)2 (up to 99:1 Z:E). Selective energy transfer from the excited state photocatalyst to the starting E-isomer ensures that directionality
据报道,使用便宜的(-)-核黄素(维生素B 2),在λ= 402 nm的辐射下,生物激发了肉桂的光催化E → Z异构化。这种操作简单的转化过程与一系列酰胺衍生物兼容,包括–NR 2,–NHSO 2 R和N(Boc)2(最高99:1 Z:E)。从激发态光催化剂到起始E-异构体的选择性能量转移可确保实现方向性:与Z相似的过程-异构体效率低下,因为它会产生烯丙基应变,从而导致生色团解偶联。X射线分析和Stern-Volmer光猝灭研究支持了这一点。通过掺入基于肉桂酰胺的氨基酸,公开了操纵简单模型Leu-脑啡肽五肽构象的方法的初步验证。