Ring Opening of 1,5-Dioxaspiro[3.2]hexanes: Selective Preparation of α-Heterofunctionalized-β‘-hydroxy Ketones or 2,2-Disubstituted Oxetanes
摘要:
[GRAPHICS]2-Methyleneoxetanes have been converted into 1,5 dioxaspiro[3.2]hexanes with dimethyldioxirane. Reaction of the dioxaspirohexanes with a range of heteroatom nucleophiles, hydride donors, or organoaluminum reagents was successful under neutral or mild conditions, affording, selectively, polyfunctionalized ketones or 2,2 disubstituted oxetanes.
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