- Synthesis of Trimethyl α-Keto Trithioorthoesters and Dimethyl α-Keto Dithioacetals by Reaction of Esters with Tris(methylthio)methyllithium
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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 α-keto trithioorthoesters 3 or, alternatively, the dimethyl α-keto dithioacetals 4.The reaction mechanism has been elucidated.
- Barbero, Margherita,Cadamuro, Silvano,Degani, Iacopo,Dughera, Stefano,Fochi, Rita
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p. 6017 - 6024
(2007/10/03)
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- Synthetic Application of Lithiated Tris(methylthio)methane: Preparation of Aliphatic Methyl Thiolcarboxylates from the Corresponding Halides. Convenient Synthesis of Tris(methylthio)methane
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A thorough study directed towards the synthesis of methyl thiolcarboxylates was made on the basis of the following steps: (i) conversion of alkyl halides into the corresponding trimethyl trithioorthocarboxylates by using tris(methylthio)methyllithium in THF at -78 degC; (ii) selective hydrolysis of the intermediates to methyl thiolcarboxylates by using 35percent aq.HBF4 in DMSO or, in some cases, in THF.The overall yields of the two stages are, usually, between 70 and 88percent.By this procedure it is also possible to incorporate 18O in the carbonyl group of thiol esters (ca. 98percent isotopic purity).Furthermore, a new, convenient method for the preparation of tris(methylthio)methane as the precursor of tris(methylthio)methyllithium was developed.
- Barbero, Margherita,Cadamuro, Silvano,Degani, Iacopo,Dughera, Stefano,Fochi, Rita
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p. 2075 - 2080
(2007/10/02)
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- Synthetic Application of Tris(methylthio)methyl Salts. An Efficient Route to Trithioorthocarboxylic Esters from Strongly Activated Aromatic and Heteroaromatic Systems
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Nine trithioorthocarboxylic esters were synthesized by reaction of tris(methylthio)methyl methyl sulfate or tetrafluoroborate with electron-rich aromatic and heteroaromatic compounds, i.e.N,N-dialkylarylamines, pyrroles, and indoles.The new procedure is simple and offers the following advantages: easy preparation of reagents; mild reaction condition; possibility to introduce two tris(methylthio)methyl groups into the same ring, good to excellent yields.
- Barbero, Margherita,Cadamuro, Silvano,Degani, Iacopo,Fochi, Rita,Gatti, Antonella,Regondi, Valeria
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