Highly Efficient Generation of Ammonium Eneselenolates, Their Reactions and Electronic Properties
作者:Toshiaki Murai、Shuuya Hayakawa、Shinzi Kato
DOI:10.1246/cl.2000.368
日期:2000.4
The ammonium eneselenolates generated from selenothioic acid S-esters and ammonium fluoride were reacted with carbon electrophiles to furnish ketene selenothioacetals with high stereoselectivities. The spectroscopic properties of the ammonium eneselenolates have suggested that the electrons on the selenium atom efficiently delocalize on the carbon-carbon double bond.
The reaction of lithium alkyneselenolates generated from lithium alkynides and selenium powder with a variety of thiols afforded selenothioic acid S-alkyl esters in moderate to high yields. The product yields were highly dependent on the substituents of the starting acetylenes. The formation of unstable S-aryl ester was confirmed by the enolization followed by alkylation.
smoothly with the extrusion of selenium atoms to afford α-phosphoryl sulfides 2 in good to high yields. A similar reaction takes place more easily with dimethyl phenylphosphonite and methyl diphenylphosphinite, although the ketene selenothioacetals 3 are also formed as by-products in increased yields. The use of diselenoic acid esters 1f and 1g gives α-phosphoryl selenides 2m and 2n. The products exhibit characteristic
Reactions of Selenothioic Acid<i>S</i>-Esters and Diselenoic Acid Esters with Trialkyl Phosphites Leading to<i>α</i>-Phosphoryl Sulfides and Selenides
作者:Toshiaki Murai、Chiyoko Izumi、Shinzi Kato
DOI:10.1246/cl.1999.105
日期:1999.2
The reaction of selenothioic acid S-esters with trialkyl phosphites proceeded smoothly to afford α-phosphoryl sulfides as a major product in good to high yields. The reaction was also applicable to diselenoic acidesters. On the contrary, selenothioic acid S-butyl ester underwent oxidative dimerization with triphenylphosphine to give a divinyl diselenide.
Selenothioic acid S-alkyl esters were reacted with allylic bromides in the presence of Et3N. Mono-, di- or tri-allylatd products were selectively formed by changing reaction temperatures, times and allylic bromides used. The reaction proceeded with high regio- and stereoselectivity via the seleno-Claisen rearrangement. The selective synthesis of monoallylated esters was also attained by the reaction