alpha,alpha-Bis(phenylseleno)ketones have been synthesized by phenylselenenylation of enolates derived from alpha-phenylseleno ketones. Depending on the structure of the ketones, three experimental procedures were adopted.
titanium enolates of α-seleno esters in the presence of Ph3P or Ph3PO gave the products with high stereoselectivity favoring the syn isomers. Reaction of α-seleno ketones with TiCl4 in the presence of 2 equiv. of Et3N, and subsequently with aldehydes, gave the aldol products with high syn selectivity. The stereoselectivity in the aldol reaction of 3-pentanone also increased by using an excess amount of Et3N
A new synthetic method of organoselenium compounds has been developed. When phenyl tributylstannyl selenide (PhSeSnBu3) was allowed to react with acyl or aroyl chlorides in the presence of a catalytic amount of a palladium complex such as Pd(PPh3)(4), Se-phenyl selenol esters were obtained in moderate to good yields. Similarly, the palladium complex catalyzed the reaction of PhSeSnBu3 with alpha-halo carbonyl compounds to afford the corresponding alpha-phenyseleno carbonyl compounds in moderate yields.
Regiodefined synthesis of α-bromo, α-phenylthio, and α-phenylseleno ketones by means of specific substitution of the trimethylsilyl group in α-trimethylsilyl ketones
作者:Isamu Matsuda、Susumu Sato
DOI:10.1016/0022-328x(86)80349-7
日期:1986.10
MATSUDA ISAMU; SATO SUSUMU, J. ORGANOMET. CHEM., 314,(1986) N 1-2, 47-52