130925-76-7Relevant articles and documents
A polymer-supported scandium catalyst
Kobayashi, Shu,Nagayama, Satoshi
, p. 2256 - 2257 (1996)
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Aryl-substituted dimethylbenzimidazolines as effective reductants of photoinduced electron transfer reactions
Hasegawa, Eietsu,Ohta, Taku,Tsuji, Shiori,Mori, Kazuma,Uchida, Ken,Miura, Tomoaki,Ikoma, Tadaaki,Tayama, Eiji,Iwamoto, Hajime,Takizawa, Shin-Ya,Murata, Shigeru
, p. 5494 - 5505 (2015/08/03)
Photoinduced electron transfer (PET) reactions promoted by 2-aryl substituted 1,3-dimethylbenzimidazolines (Ar-DMBIH) were investigated. Excited states of Ar-DMBIH, formed by irradiation using light above 360 nm, initiate PET reductions of various organic substrates, including transformations of epoxy ketones to aldols, free radical rearrangements such as the Dowd-Beckwith ring-expansion and 5-exo hexenyl cyclization, deprotection of N-sulfonyl-indols, and allylation of acyl formates. In these processes, Ar-DMBIH possessing 1-naphthyl, 2-naphthyl, 1-pyrenyl and 9-anthryl substituents formally act as two electron and one proton donors while the hydroxynaphthyl substituted derivative serves as a two electron and two proton donor. On the basis of the results of absorption spectroscopy studies, cyclic voltammetry and DFT calculation, a mechanistic sequence for these reduction reactions is proposed that involves initial photoexcitation of the aryl chromophore of the Ar-DMBIH followed by single electron transfer (SET) to the organic substrate to generate the radical cation of benzimidazoline and the radical anion of the substrate.
Catalytic use of zinc amide for transmetalation with allylboronates: General and efficient catalytic allylation of carbonyl compounds, imines, and hydrazones
Cui, Yi,Li, Wei,Sato, Takehiro,Yamashita, Yasuhiro,Kobayashi, Shu
supporting information, p. 1193 - 1205 (2013/06/04)
The efficient catalytic allylation of ketones, imines, and hydrazones with allylboronates using a catalytic amount of zinc amide is reported. In this reaction, the boron-to-zinc exchange process occurred smoothly to afford the corresponding allylzinc amides, and the desired allylation reactions proceeded in high efficiency (～0.1mol%). A mechanistic study revealed that transmetalation was a rate-determining step in the catalytic cycle, and also that the amide ligand on the zinc center played a key role in preparing reactive allylzinc species. Catalytic asymmetric allylations were also investigated, and high enantioselectivities were obtained using chiral diamine ligands. Copyright
Mesoporous aluminosilicate-catalyzed allylation of carbonyl compounds and acetals
Ito, Suguru,Hayashi, Akira,Komai, Hirotomo,Yamaguchi, Hitoshi,Kubota, Yoshihiro,Asami, Masatoshi
experimental part, p. 2081 - 2089 (2011/04/19)
A mesoporous aluminosilicate (Al-MCM-41) was found to be an effective heterogeneous catalyst for the reaction of both carbonyl compounds and acetals with allylsilanes to afford the corresponding homoallyl silyl ethers and homoallyl alkyl ethers, respectively. Both the mesoporous structure and the presence of aluminum moiety were indispensable for the high catalytic activity of Al-MCM-41. Moreover, Al-MCM-41 could catalyze the reaction of acetals chemoselectively in the presence of the corresponding carbonyl compounds. The solid acid catalyst Al-MCM-41 could be recovered easily by filtration and could be reused three times without a significant loss of catalytic activity.
