Hiroto Owada

Phenylselenenyl chloride in acetonitrile-water: a highly convenient reagent for hydroxyselenation of olefins and preparation of cyclic ethers from dienes

Abstract The reaction of phenylselenenyl chloride with olefins in aqueous acetonitrile affords β-hydroxyalkyl phenyl selenides in excellent yields, providing the most 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.

An improved method for olefin synthesis using pyridylseleno group as a leaving group

Abstract Alkyl pyridyl selenides are oxidized by 1.5 equiv. of 30% H 2 O 2 in the THF to give olefins in good to excellent yields. The yields are always higher than the case where alkyl phenyl selendies are used under the same conditions.

Enone synthesis via α-pyridylseleno carbonyl compounds

Abstract Oxidative elimination of α-pyridylseleno carbonyl compounds affords enones in excellent yields, providing an improved method for dehydrogenation of ketones and aldehydes. These results indicate that pyridylseleno group is a better leaving group than phenylseleno group in selenoxide elimination leading to enones.

Highly convenient method for hydroxyselenation of olefins

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.

Pyridylseleno group in organic synthesis. Part 4. Oxyseleniation of olefins using pyridine-2-selenenyl bromide as a selenium reagent and its utilization in the synthesis of 2-pyridyl vinylic selenides

The reaction of olefins with pyridine-2-selenenyl bromide in methanol as solvent affords β-methoxyalkyl 2-pyridyl selenides (A) in good to excellent yields. This reaction also proceeds in acetic acid and aqueous tetrahydrofuran to give acetoxyseleniated and hydroxyseleniated products respectively. Oxidative elimination of (A) proceeds at room temperature, even in the case where the 2-pyridylseleno group is located at a terminal carbon, to afford methyl vinylic ethers in good yield. Treatment of (A) with lithium di-isopropylamide produces 2-pyridyl vinylic selenides (B). Deprotonation of (B) can be carried out under milder conditions than those of the corresponding phenyl vinylic selenides.