Synthesis of Trimethyl α-Keto Trithioorthoesters and Dimethyl α-Keto Dithioacetals by Reaction of Acyl Chlorides, Anhydrides, Thiol Esters, and N,N-Dimethylamides with [Tris(methylthio)methyl]lithium
RhH(PPh3)4, 1,2-bis(diphenylphosphino)ethane (dppe), and dimethyl disulfide, ketones without α-activating groups were α-methylthiolated with 1,2-diphenyl-2-methylthio-1-ethanone giving α-methylthio ketones. The reaction of unsymmetrical ketones proceeded at the more substituted carbons. The initial formation of kinetic α-methylthiolated products followed by their rearrangement to thermodynamic products was
Synthesis of trimethyl .alpha.-keto trithioorthoesters and dimethyl .alpha.-keto dithioacetals by reaction of esters with tris(methylthio)methyllithium
A complete study has been made of the reaction of tris(methylthio)methyllithium with aromatic, heteroaromatic, and aliphatic esters. It is a one-pot reaction that despite its complexity, and depending on the reagent ratios, the reaction conditions, and the possible use of additional reagents (N-(methylthio)phthalimide or BuLi), can supply easily, in excellent and reproducible yields, the trimethyl alpha-keto trithioorthoesters 3 or, alternatively, the dimethyl a-keto dithioacetals 4. The reaction mechanism has been elucidated.
1-(2,5-Dichlorophenyl)-2,2-bis(methylsulfanyl)vinyl Esters as Highly Efficient Chemoselective Acylating Reagents
作者:Iacopo Degani
DOI:10.1055/s-1999-3529
日期:1999.7
Synthesis of Trimethyl α-Keto Trithioorthoesters and Dimethyl α-Keto Dithioacetals by Reaction of Acyl Chlorides, Anhydrides, Thiol Esters, and <i>N</i>,<i>N</i>-Dimethylamides with [Tris(methylthio)methyl]lithium