591-24-2Relevant articles and documents
Radical anion ring opening reactions via photochemically induced electron transfer
Cossy,Aclinou,Bellosta,Furet,Baranne-Lafont,Sparfel,Souchaud
, p. 1315 - 1316 (1991)
Ketyl radical anions can induce the opening of adjacent strained ring such as cyclopropane, cyclobutane, epoxide and 7-oxabicyclo[2.2.1]hepane.
Stereocontrol with lithium trimethylzincate toward gibberellin synthesis
Isobe, Minoru,Chiang, Ching-Te,Tsao, Kuo-Wei,Cheng, Chia-Yi,Bruening, Reimar
, p. 2109 - 2113 (2012)
Substrate control in target-oriented synthesis is generally important in establishing the required stereogenic center rather than reagent control. During the course of the total synthesis toward Gibberellin A3 (1), a model compound (21) as the A-ring of 1 was accomplished in five overall steps with an overall yield of 15 %, starting from furfural through conjugate addition of lithium trimethylzincate to oxabicyclo[2.2.1]heptadienedicarboxylic ester (2) as the key step. Relative to more common lithium dimethylcuprate or aluminum reagents, this zincate complex showed a complete selectivity with higher reactivity than with other simple enone compounds. The incoming methyl group was 100 % selective from the ring oxygen side of 2, and the enolate intermediate can be protonated stereoselectivly without the bridge-oxygen-ring opening.
Selective hydrogenation of phenol to cyclohexanone over Pd nanoparticles encaged hollow mesoporous silica catalytic nanoreactors
Li, Kaijie,Wang, Junyou,Yang, Caoping,Zhou, Shenghu
, (2020/12/25)
Pd nanoparticles (NPs) encaged hollow mesoporous silica nanoreactors (Pd?HMSNs) are prepared for hydrogenations of phenol, cresols and chlorophenols to cyclohexanone derivatives. Pd?HMSNs feature ～ 4 nm Pd NPs in ～ 16 nm hollow cavities of ～ 30 nm HMSNs. Such Pd?HMSNs are highly thermally and catalytically stable. At mild reaction conditions, Pd?HMSNs efficiently catalyze hydrogenations of phenol and m-cresol to cyclohexanone derivatives with ≥ 98.3 % selectivity at ≥ 99.0 % conversions. Hydrogenations of o- and m-chlorophenol over Pd?HMSNs give cyclohexanone with ≥ 97.3 % selectivity at 100.0 % conversions, demonstrating a beneficial effect of such HMSNs for consecutive reactions. The confinement of Pd NPs inside hollow cavities of mesoporous nanoreactors greatly promotes collision times of reactant molecules with Pd NPs, resulting in an enhanced catalytic efficiency, while the residence of Pd NPs inside cavities provides a protecting effect for Pd NPs and is beneficial to thermal and catalytic stabilities.
Photoredox-Catalyzed Simultaneous Olefin Hydrogenation and Alcohol Oxidation over Crystalline Porous Polymeric Carbon Nitride
Qiu, Chuntian,Sun, Yangyang,Xu, Yangsen,Zhang, Bing,Zhang, Xu,Yu, Lei,Su, Chenliang
, p. 3344 - 3350 (2021/07/26)
Booming of photocatalytic water splitting technology (PWST) opens a new avenue for the sustainable synthesis of high-value-added hydrogenated and oxidized fine chemicals, in which the design of efficient semiconductors for the in-situ and synergistic utilization of photogenerated redox centers are key roles. Herein, a porous polymeric carbon nitride (PPCN) with a crystalline backbone was constructed for visible light-induced photocatalytic hydrogen generation by photoexcited electrons, followed by in-situ utilization for olefin hydrogenation. Simultaneously, various alcohols were selectively transformed to valuable aldehydes or ketones by photoexcited holes. The porosity of PPCN provided it with a large surface area and a short transfer path for photogenerated carriers from the bulk to the surface, and the crystalline structure facilitated photogenerated charge transfer and separation, thus enhancing the overall photocatalytic performance. High reactivity and selectivity, good functionality tolerance, and broad reaction scope were achieved by this concerted photocatalysis system. The results contribute to the development of highly efficient semiconductor photocatalysts and synergistic redox reaction systems based on PWST for high-value-added fine chemical production.
