Activation of molecular oxygen and its use in stereoselective tetrahydrofuran-syntheses from δ,ε-unsaturated alcohols
作者:Bárbara Menéndez Pérez、Dominik Schuch、Jens Hartung
DOI:10.1039/b804588g
日期:——
2-propanol at 60 degrees C. Ring closures occurred diastereoselectively and afforded 2,3-trans- (96% de), 2,4-cis- (approximately 60% de), and 2,5-trans-substituted (>99% de) (phenyl)tetrahydrofur-2-ylmethanols as major components. Formation of bicyclic compounds and a 2,3,4,5-substituted oxolane was feasible as exemplified by syntheses of oxabicyclo[4.3.0]nonylmethanols and a derivative of natural product
如果用O(2)和bis 2,2,2-三氟甲基-1-[(1R,4S)-1,7,7处理-三甲基-2-(氧代-κ)双环[2.2.1]庚-3-基]乙醇基-}钴(ii)在2-丙醇溶液中在60摄氏度下发生。非对映选择性发生闭环反应,得到2,3 -反-(96%de),2,4-顺-(约60%de)和2,5-反-取代(> 99%de)(苯基)四氢呋喃-2-基甲醇为主要成分。双环化合物和2,3,4,5-取代的环氧丙烷的形成是可行的,例如在61-72%(de-90-99%)中合成了oxabicyclo [4.3.0]壬基甲醇和天然产物厚朴素的衍生物。四氢呋喃合成的有效性主要取决于(i)溶剂,(ii)反应温度,(iii)初始钴浓度,(iv)羟基和乙烯基之间的链长,和(v)在反应实体上的取代。提出了用于合理化观察到的选择性的序列。