Directed Ring-Opening of 1,5-Dioxaspiro[3.2]hexanes: Selective Formation of 2,2-Disubstituted Oxetanes
作者:Rosa Taboada、Grace G. Ordonio、Albert J. Ndakala、Amy R. Howell、Paul R. Rablen
DOI:10.1021/jo0206465
日期:2003.2.1
nucleophiles provide 2,2-disubstituted oxetanes. Herein, the results of reactions of 3-phenyl-1,5-dioxaspiro[3.2]hexane with a variety of nitrogen-containing heteroaromatic bases are reported. There appears to be a correlation between the pK(a) of the nucleophile and the reaction outcome with more acidic nucleophiles providing 2,2-disubstituted oxetanes. Moreover, the mode of ring opening can be directed toward
1,5-二氧杂螺并[3.2]己烷与许多杂原子亲核试剂发生开环反应,以提供α-取代的β'-羟基酮。然而,某些路易斯酸性亲核试剂提供2,2-二取代的氧杂环丁烷。在此,报道了3-苯基-1,5-二氧杂螺[3.2]己烷与各种含氮杂芳族碱的反应结果。亲核试剂的pK(a)与反应结果之间存在相关性,酸性更高的亲核试剂可提供2,2-二取代的氧杂环丁烷。此外,可通过添加路易斯酸将开环的方式导向取代的氧杂环丁烷。通过使用从头算分子轨道方法计算各种可能的反应途径的势能表面上的固定点,可以使这些结果合理化。