Formation of Some Oxygen-Containing Heterocycles by Radical Cyclization: The Stereochemical Influence of Anomeric Effects
摘要:
The influence of the anomeric effect on radical cyclization has been examined by determining the stereochemical outcome of the ring closure of 10 suitably substituted radicals. The stereochemistry of the products formed from the acyclic precursors 4a-f indicates that for suitably constituted radicals anomeric interactions stabilize pseudoaxially substituted transition structures 14 thus affording products with stereochemistry the reverse of that normally observed.
Addition of silver nitrite to 2-bromoalkyl phenyl selenide in the presence of mercury(II) chloride afforded 2-nitroalkyl phenyl selenide, which upon oxidative deselenenylation provided the conjugatednitroalkene in excellent yield.
convenient method for hydroxyselenation of olefins so far reported. When the reaction was applied to conjugated dienes, monohydroxyselenated products were obtained in good to excellent yields. From non-conjugated dienes, on the other hand, cyclic ethers containing two phenylseleno groups were produced in good to excellent yields, the first step of this reaction being the hydroxyselenation of one double bond
Reaction of phenylselenyl chloride with olefins in aqueous acetonitrile affords β-hydroxyselenides (2) in excellent yields, providing a most convenient method for the hydroxyselenation of olefins.
One-pot Synthesis of Vinyl Phosphonates from 2-hydroxyalkyl Phenyl Selenides with Monoethyl Esters of Phosphonic Acid
作者:Shou-Ri Sheng、Wu-Kang Sun、Ming-Gang Hu、Xiao-Ling Liu、Qiu-Ying Wang
DOI:10.3184/030823407x198221
日期:2007.2
Vinyl phosphonates were prepared with good yields in a one-pot, two-step transformation by Mitsunobu reaction of 2-hydroxyalkyl phenylselenides with monoethyl esters of phosphonic acid followed by oxidation-elimination.
Stereo- and Regioselective Zinc-Mediated Ring-Opening of Epoxides with Diselenides
作者:Barahman Movassagh、Mojgan Shamsipoor
DOI:10.1055/s-2005-865224
日期:——
Two convenient rapid, efficient, stereoselective and highly regioselective methods for the synthesis of β-hydroxy selenides by the direct opening of epoxides with diselenides in acetonitrile in the presence of either Zn/AlCl3 or zinc powder in aqueous sodium hydroxide solution are described. These methods appear to be competitive with the other methods previously reported.