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
Allylations of selenothioic acid S-alkyl esters with allylic bromides in the presence of Et3N in THF took place selectively at the α-position of selenocarbonyl group to give allylated products with high regio- and stereo-selectivity.
Reductive cyclization of gamma,delta-unsaturated selenothioic acid S-esters with NaBH4 or LiAlH4 proceeds via delta,epsilon-unsaturated selenols to afford tetrahydroselenophenes in good to high yields.