822-50-4Relevant articles and documents
INTRAMOLECULAR CYCLIZATIONS OF ORGANOMETALLIC COMPOUNDS IV. HETEROATOM INFLUENCE ON CYCLIZATIONS OF ORGANOLITHIUM COMPOUNDS
Smith, Michael J.,Wilson, Stanley E.
, p. 4615 - 4618 (1981)
Alkoxyl groups in alkenyllithiums can influence the stereochemistry of cyclization.The presence of n-butyllithium increases the stereoselectivity such that only one stereochemistry results; the presence of TMEDA negates the heteroatom's influence so that only the other stereochemistry results.Yields are 33percent to 44percent.
Insights into the Major Reaction Pathways of Vapor-Phase Hydrodeoxygenation of m-Cresol on a Pt/HBeta Catalyst
Sun, Qianqian,Chen, Guanyi,Wang, Hua,Liu, Xiao,Han, Jinyu,Ge, Qingfeng,Zhu, Xinli
, p. 551 - 561 (2016/02/20)
Conversion of m-cresol was studied on a Pt/HBeta catalyst at 225-350°C and ambient hydrogen pressure. At 250°C, the reaction proceeds through two major reaction pathways: (1) direct deoxygenation to toluene (DDO path); (2) hydrogenation of m-cresol to methylcyclohexanone and methylcyclohexanol on Pt, followed by fast dehydration on Br?nsted acid sites (BAS) to methylcyclohexene, which is either hydrogenated to methylcyclohexane on Pt or ring-contracted to dimethylcyclopentanes and ethylcyclopentane on BAS (HYD path). The initial hydrogenation is the rate-determining step of the HYD path as its rate is significantly lower than those of subsequent steps. The apparent activation energy of the DDO path is 49.7 kJ mol-1 but the activation energy is negative for the HYD path. Therefore, higher temperatures lead to the DDO path becoming the dominant path to toluene, whereas the HYD path, followed by fast equilibration to toluene, is less dominant, owing to the inhibition of the initial hydrogenation of m-cresol.
Synthesis, reactivity, and catalytic application of a nickel pincer hydride complex
Breitenfeld, Jan,Scopelliti, Rosario,Hu, Xile
experimental part, p. 2128 - 2136 (2012/06/01)
The nickel(II) hydride complex [(MeN2N)Ni-H] (2) was synthesized by the reaction of [(MeN2N)Ni-OMe] (6) with Ph2SiH2 and was characterized by NMR and IR spectroscopy as well as X-ray crystallography. 2 was unstable in solution, and it decomposed via two reaction pathways. The first pathway was intramolecular N-H reductive elimination to give MeN2NH and nickel particles. The second pathway was intermolecular, with H2, nickel particles, and a five-coordinate Ni(II) complex [(MeN2N)2Ni] (8) as the products. 2 reacted with acetone and ethylene, forming [( MeN2N)Ni-OiPr] (9) and [(MeN 2N)Ni-Et] (10), respectively. 2 also reacted with alkyl halides, yielding nickel halide complexes and alkanes. The reduction of alkyl halides was rendered catalytically, using [(MeN2N)Ni-Cl] (1) as catalyst, NaOiPr or NaOMe as base, and Ph2SiH2 or Me(EtO)2SiH as the hydride source. The catalysis appears to operate via a radical mechanism.
Avoiding olefin isomerization during decyanation of alkylcyano α,ω-dienes: A deuterium labeling and structural study of mechanism
Rojas, Giovanni,Wagener, Kenneth B.
, p. 4962 - 4970 (2008/12/20)
(Chemical Equation Presented) A two-step synthetic pathway involving decyanation chemistry for the synthesis of pure alkyl α,ω-dienes in quantitative yields is presented. Prior methodologies for the preparation of such compounds required 6-9 steps, sometimes leading to product mixtures resulting from olefin isomerization chemistry. This isomerization chemistry has been eliminated. Deuteration labeling and structural mechanistic investigations were completed to decipher this chemistry. Deuterium labeling experiments reveal the precise nature of this radical decyanation chemistry, where an alcohol plays the role of hydrogen donor. The correct molecular design to avoid competing intramolecular cyclization, and the necessary reaction conditions to avoid olefin isomerization during the decyanation process are reported herein.
