Neighboring Group Participation of Phosphine Oxide Functionality in the Highly Regio- and Stereoselective Iodohydroxylation of 1,2-Allenylic Diphenyl Phosphine Oxides
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- 作者：Hao Guo ; Rong Qian ; Yinlong Guo ; Shengming Ma
- 刊名：Journal of Organic Chemistry
- 出版年：2008
- 出版时间：October 17, 2008
- 年：2008
- 卷：73
- 期：20
- 页码：7934-7938
- 全文大小：215K
- 年卷期：v.73,no.20(October 17, 2008)
- ISSN：1520-6904
文摘
Two sets of reaction conditions were established to enable the highly regio- and stereoselective iodohydroxylation of 1,2-allenylic diphenyl phosphine oxides, yielding (E)-2-iodo-3-hydroxy-1-alkenyl diphenyl phosphine oxides with very high stereoselectivity. The scope of this reaction was examined extensively. Notably, studies on the reactivity of optically active substrates indicated that the axial chirality in the starting allenes may be efficiently transferred to the center chirality of the products with no discernible loss of enantiopurity. Due to the importance of phosphine-containing compounds, both as reagents and ligands, this reaction shows potentials in organic synthesis. Investigations using ESI-MS technology on the 18O-labeled product, which was prepared using 18O-water as the solvent, indicated that the 18O atom was bound to phosphorus in the final product and the oxygen atom of the hydroxyl comes from the phosphinyl functionality of the allene reactant. These results provided solid evidence for the formation of a five-membered cyclic intermediate from the neighboring group participation of the diphenylphosphinyl group. To the best of our knowledge, this is the first time that the neighboring group participation of this type of group was observed.