Addition reactions of alkenes with electronegatively substituted alcohols in the presence of xenon difluoride
作者:Melvin L. Druelinger、Dale F. Shellhamer、Robert D. Chapman、Scott A. Shackelford、Maurice E. Riner、Steven L. Carter、Ryan P. Callahan、Cameron R. Youngstrom
DOI:10.1039/a604677k
日期:——
The electrophilic reactivity of proposed alkoxyxenon fluoride (ROXeF)
intermediates based on electronegatively substituted (polyfluorinated
and polynitroaliphatic) alcohols has been characterized with model
alkenes norbornene, 2-methylpent-1-ene and hex-1-ene. The alkoxyxenon
fluorides can react as positive oxygen electrophiles—initially
incorporating alkoxy substituents—or as apparent fluorine
electrophiles—resulting in initial fluorine
incorporation—depending on conditions. Efficient simple addition
of poorly nucleophilic alcohols to norbornene was observed in certain
systems. Selectivity between the various reaction paths (simple
fluorination, alkoxyfluorination or alcohol addition) was observed to be
a sensitive function of various reaction conditions, especially solvent,
temperature and catalyst.
根据电负性取代的(多氟化和多硝基脂肪族)醇,提出的醇氧氟氙(ROXeF)中间体的电亲反应性已通过模型烯烃如内苯、2-甲基戊-1-烯和己-1-烯进行表征。这些醇氧氟氙可作为正氧电亲体反应——最初引入醇氧取代基——或作为表观氟电亲体反应——导致初始氟的引入——具体取决于反应条件。在某些体系中,观察到欠亲核醇与内苯之间的高效简单加成。不同反应路径(简单氟化、醇氧氟化或醇加成)之间的选择性被认为是各种反应条件的敏感函数,特别是溶剂、温度和催化剂。