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
Photoinduced Palladium-Catalyzed Carbofunctionalization of Conjugated Dienes Proceeding via Radical-Polar Crossover Scenario: 1,2-Aminoalkylation and Beyond
作者:Kelvin Pak Shing Cheung、Daria Kurandina、Tetsuji Yata、Vladimir Gevorgyan
DOI:10.1021/jacs.0c03993
日期:2020.6.3
A photoinduced palladium-catalyzed 1,2-carbofunctionalization of conjugateddienes has been developed. This mild modular approach, which does not require employment of exogeneous photosensitizers and external oxidants, allows for efficient and highly regio- and ste-reoselective synthesis of a broad range of allylic amines from readily available 1,3-dienes, alkyl iodides, and amines. Employment of O-
This invention relates to compounds and pharmaceutical compositions, and methods for inhibiting or preventing the amyloid protein deposits in the brain which are associated with Alzheimer's disease and aged Down's syndrome patients. More particularly, it relates to the treatment of Alzheimer's disease.
Preparation of alka-2,4-dienylsilanes and 3-cyclopropylprop-2-enylsilanes by the titanocene(II)-promoted reaction of 2,4-bis(phenylthio)but-3-enylsilanes
Preparation of allylsilanes by the Cp2Ti[P(OEt)3]2 (1)-promoted reaction of 2,4-bis(phenylthio)but-3-enylsilanes 5 is described. The olefination of carbonyl compounds 6 using the silanes 5 and the low-valent titanium species 1 produced alka-2,4-dienylsilanes 2. 3-Cyclopropylprop-2-enylsilanes 3 were obtained by the reaction of 5 with 1 in the presence of terminal olefins 9.
描述了通过Cp 2 Ti [P(OEt)3 ] 2(1)促进的2,4-双(苯硫基)丁-3-烯基硅烷5反应制备烯丙基硅烷。使用硅烷5和低价钛物质1对羰基化合物6进行的烯烃化反应产生了碱2,4-二烯基硅烷2。通过5与1在末端烯烃9的存在下反应,获得3-环丙基丙-2-烯基硅烷3。
Preparation of allylsilanes by the olefination of carbonyl compounds using β-silylthioacetals
Titanocene(II)-promoted olefination of various carbonyl compounds using 1,1-bis(phenylthio)-2-triorganosilylethanes gave allylsilanes in good yields. γ-Alkoxy and alkylthio group substituted allylsilanes were also obtained by using carboxylic esters and thiolesters, respectively.