(Cyclopentadienone)iron-Catalyzed Transfer Dehydrogenation of Symmetrical and Unsymmetrical Diols to Lactones
作者:Yidan Tang、Rowan I. L. Meador、Casina T. Malinchak、Emily E. Harrison、Kimberly A. McCaskey、Melanie C. Hempel、Timothy W. Funk
DOI:10.1021/acs.joc.9b01884
日期:2020.2.21
detected. The lactonization of unsymmetrical diols containing two primary alcohols occurred with catalyst 1, but selectivity was low based on alcohol electronics and modest based on alcohol sterics. Evidence for a transfer dehydrogenation mechanism was found, and insight into the origin of selectivity in the lactonization of 1°/2° diols was obtained. Additionally, spectroscopic evidence for a trimethylamine-ligated
在使用丙酮作为溶剂和氢受体的脱氢二醇内酯化反应中,探索了具有可变取代基的带有环戊二烯酮配体的空气稳定的羰基铁化合物。[2,5-(SiMe3)2-3,4-(CH2)4(η4-C4C═O)] Fe(CO)3(2)和[[2,5-(SiMe3)2-3,4-(CH2)4(η4-C4C═O)]发现2,5-(SiMe3)2-3,4-(CH2)3(η4-C4C═O)] Fe(CO)3(2)活性最高,其中2选择性最高包含伯醇和仲醇的二醇的内酯化。已成功合成了包含五元,六元和七元环的内酯,并且未检测到羧酸的过氧化。含有两种伯醇的不对称二醇的内酯化反应在催化剂1的作用下发生 但基于酒精电子学的选择性较低,而基于酒精立体位的选择性较低。发现了转移脱氢机理的证据,并且获得了对1°/ 2°二醇的内酯化中选择性的起源的见解。另外,发现在反应过程中在溶液中形成三甲胺连接的铁物质的光谱学证据。