Efficient Epoxidation of Alkenes with Aqueous Hydrogen Peroxide Catalyzed by Methyltrioxorhenium and 3-Cyanopyridine
作者:Hans Adolfsson、Christophe Copéret、Jay P. Chiang、Andrei K. Yudin
DOI:10.1021/jo005623+
日期:2000.12.1
The epoxidation of alkenes with 30% aqueous hydrogen peroxide is catalyzed efficiently by methyltrioxorhenium (MTO) in the presence of pyridine additives. The addition of 1-10 mol % of 3-cyanopyridine increases the system's efficiency for terminal and trans-disubstituted alkenes resulting in high isolated yields of the corresponding epoxides. The system allows for epoxidation of alkenes with various
Activation Parameters for the Epoxidation of Substitutedcis/trans Pairs of 1,2-Dialkylalkenes by Dimethyldioxirane
作者:Brian S. Crow、W. Rucks Winkeljohn、Angela Navarro-Eisenstein、Elba Michelena-Baez、Paul J. Franklin、Pedro C. Vasquez、Al Baumstark
DOI:10.1002/ejoc.200600427
日期:2006.10
the corresponding cisisomers. The ΔH‡ terms mirrored trends observed in ΔG‡ because ΔS‡ terms for all ten of the compounds were roughly identical. The ΔΔG‡ values, a comparison of the trans to the cisisomer data, yielded positive values of 1.2 to 1.8 kcal/mol for the five sets of data and appeared to be dependent on relative steric interactions. The experimental activationparameter data, consistent
The direct arylation of allylic sp3 C–H bonds via organic and photoredox catalysis
作者:James D. Cuthbertson、David W. C. MacMillan
DOI:10.1038/nature14255
日期:2015.3.5
particular, the direct arylation of non-functionalized allylic systems would enable access to a series of known pharmacophores (molecular features responsible for a drug’s action), though a general solution to this long-standing challenge remains elusive. Here we report the use of both photoredox and organic catalysis to accomplish a mild, broadly effective direct allylic C–H arylation. This C–C bond forming
未活化的 sp3 C-H 键的直接功能化仍然是合成有机化学家面临的最具挑战性的问题之一。这种转变的吸引力来自于它们通过简单和其他惰性结构单元的耦合促进复杂有机分子构建的能力,而不会引入无关的官能团。尽管最近做出了显着的努力,但事实证明,为 sp3 C-H 键参与 C-C 键形成反应建立一般和温和的策略是困难的。在此背景下,发现能够以催化方式直接使烯丙基甲基、亚甲基和次甲基碳官能化的化学转化是当务之急。尽管烯丙基 C-H 键的直接氧化和胺化方案(即,C-H 键,其中相邻的碳参与 C = C 键)已经广泛建立,烯丙基底物在 C-C 键形成反应中的参与迄今为止需要使用预官能化的偶联伙伴。特别是,非功能化烯丙基系统的直接芳基化将能够获得一系列已知的药效团(负责药物作用的分子特征),尽管解决这一长期挑战的通用解决方案仍然难以捉摸。在这里,我们报告了使用光氧化还原和有机催化来完成温和、广泛有效的直接烯丙基
Stereochemistry and regiochemistry of the addition of lodonium nitrate to alkenes
作者:J. William Lown、Alummoottil V. Joshua
DOI:10.1039/p19730002680
日期:——
The stereochemistry of the products was confirmed by relating them chemically with known compounds. Addition to the less hindered (Z)-[β-2H]styrene is also stereospecific, eliminating the possibility of restricted rotation during addition. Ring closure by neighbouring sulphur in the addition of iodonium nitrate to 1-allyl-3,3-diethylthiourea affords a thiazole. The failure to obtain addition and phenyl
A stereo- and regio-specific addition of η3-trimethylsilylallyltitanium compound with aldehydes. A facile and stereocontrolled synthesis of E- and Z-terminal dienes
作者:Fumie Sato、Yoshito Suzuki、Masao Sato
DOI:10.1016/s0040-4039(00)85661-0
日期:1982.1
η3-Trimethylsilyallyltitanium compound, (η5-C5H5)2Ti(η3-1-trimethylsilylallyl), reacts with aldehydes to give (±)-(R,S)-3-trimethylsilyl-4-hydroxy-1-alkenes in excellent yields, which can be deoxysilylated to either E- or Z-1,3-dienes.
η 3 -Trimethylsilyallyltitanium化合物,(η 5 -C 5 H ^ 5)2的Ti(η 3 -1-trimethylsilylallyl),与醛进行反应,得到(±) - (R,S)-3-三甲基甲硅烷基-4-羟基-1- -烯烃具有优异的收率,可以将其脱氧甲硅烷基化为E-或Z-1,3-二烯。