Organic synthesis using haloboration reaction. Part 7. A stereospecific synthesis of (Z)-.delta.-halo-.gamma.,.delta.-unsaturated ketones via haloboration reaction of terminal alkynes
One-Pot Regio- and Stereoselective Cyclization of 1,2,<i>n</i>-Triols
作者:Tao Zheng、Radha S. Narayan、Jennifer M. Schomaker、Babak Borhan
DOI:10.1021/ja043002i
日期:2005.5.1
A simple and efficient process to cyclize triols containing a 1,2-diol functionality with a pendant hydroxyl group is presented. The one-pot procedure converts the 1,2-diol into an ortho ester in situ, which upon treatment with a Lewis acid generates a cyclic acetoxonium intermediate. This intermediate is subsequently trapped by the pendant hydroxyl group to generate a cyclic ether. The stereochemistry
Oxidative cyclization of 5-hydroxyalkenes with rhenium oxide, utilizing a co-oxidant. IV
作者:Suhan Tang、Robert M. Kennedy
DOI:10.1016/s0040-4039(00)79078-2
日期:1992.9
5-Hydroxylalkenes react with rhenium(VII) oxide in the presence of another oxidant, H5IO6, to provide substituted tetrahydrofurans. The yield and stereoselectivity are comparable to stoichiometric results.
Organic synthesis using haloboration reaction. Part 7. A stereospecific synthesis of (Z)-.delta.-halo-.gamma.,.delta.-unsaturated ketones via haloboration reaction of terminal alkynes
Tightly Convoluted Polymeric Phosphotungstate Catalyst: An Oxidative Cyclization of Alkenols and Alkenoic Acids
作者:Yoichi M. A. Yamada、Haiqing Guo、Yasuhiro Uozumi
DOI:10.1021/ol070258v
日期:2007.4.1
A tightly convoluted polymeric phosphotungstate catalyst was prepared via ionic assembly of H3PW12O40 and poly(alkylpyridinium). An oxidative cyclization of various alkenols and alkenoic acids was efficiently promoted by the polymeric catalyst in aq H2O2 in the absence of organic solvents to afford the corresponding cyclic ethers and lactones in high yield. The catalyst was reused four times without loss of catalytic activity.