sequential reactions using silyl group-substituted titanium carbene complexes was studied. Dienylsilanes were obtained by the olefination of carbonyl compounds with γ-silylvinylcarbene complexes. Cyclopropanation of 1-alkenes with the vinylcarbene complexes produced (E)-(β-silylvinyl)cyclopropanes with high stereoselectivity. The reaction of β-(trialkylsilyl)carbene complexes with zinc alkoxides of homopropargyl
Titanocene(II)-promoted desulfurizative acylation of thioacetals with alkanenitriles
作者:Takeshi Takeda、Haruhiko Taguchi、Tooru Fujiwara
DOI:10.1016/s0040-4039(99)02001-8
日期:2000.1
Ketones were obtained in good yields by titanocene(II)-promoted reaction of thioacetals with alkanenitriles. The regioselective formation of α-substituted ketone was observed when the reaction was carried out in the presence of methyl iodide or benzyl bromide.
The first catalytic α-alkylation reaction of benzyl sulfides and 1,3-dithianes with styrenes and conjugated dienes was developed under mild conditions by using a readily available Brønsted base potassium bis(trimethylsilyl)amide (KHMDS) as catalyst. The reaction displayed good functional group tolerance, high efficiency, and excellent chemoselectivity. A series of desired alkylation products were obtained
Preparation of silyl polyenol ethers by carbonyl olefination of silyl esters
作者:Takeshi Takeda、Tatsuya Fukada、Akira Tsubouchi
DOI:10.1016/j.tetlet.2014.01.040
日期:2014.2
Silyl enol ethers were produced by the carbonyl olefination of silylesters with titanium carbene complexes generated by the desulfurizative titanation of thioacetals. The regioselective preparation of silyl dienol and trienol ethers has been achieved by using unsaturated silylesters and thioacetals.
The First Example of .ALPHA.-Thiomagnesiums Generated from Dithioacetal Monoxides with Grignard Reagent; Their Properties and Some Synthetic Applications.
作者:Tsuyoshi Satoh、Kiyoshi Akita
DOI:10.1248/cpb.51.181
日期:——
Dithioacetal monoxides were synthesized from aldehydes and cyclohexanone, and reaction of the dithioacetal monoxides with Grignard reagents was investigated. The dithioacetal monoxide synthesized from alkylaldehyde and 4-chlorobenzenethiol reacted with i-PrMgCl to afford the desired α-thiomagnesium in high yield. The generated α-thiomagnesium was found to be stable at room temperature and to be useful in organic synthesis. In contrast to this, the dithioacetal monoxides derived from benzaldehyde and cyclohexanone did not give satisfactory results.