59965-24-1Relevant articles and documents
Discriminating non-ylidic carbon-sulfur bond cleavages of sulfonium ylides for alkylation and arylation reactions
Fang, Jing,Li, Ting,Ma, Xiang,Sun, Jiuchang,Cai, Lei,Chen, Qi,Liao, Zhiwen,Meng, Lingkui,Zeng, Jing,Wan, Qian
supporting information, p. 288 - 292 (2021/07/25)
A sulfonium ylide participated alkylation and arylation under transition-metal free conditions is described. The disparate reaction pattern allowed the separate activation of non-ylidic S-alkyl and S-aryl bond. Under acidic conditions, sulfonium ylides serve as alkyl cation precursors which facilitate the alkylations. While under alkaline conditions, cleavage of non-ylidic S-aryl bond produces O-arylated compounds efficiently. The robustness of the protocols were established by the excellent compatibility of wide variety of substrates including carbohydrates.
Photo-triggered hydrogen atom transfer from an iridium hydride complex to unactivated olefins
Guo, Xingwei,Pfund, Bj?rn,Schreier, Mirjam R.,Wenger, Oliver S.
, p. 8582 - 8594 (2020/09/07)
Many photoactive metal complexes can act as electron donors or acceptors upon photoexcitation, but hydrogen atom transfer (HAT) reactivity is rare. We discovered that a typical representative of a widely used class of iridium hydride complexes acts as an H-atom donor to unactivated olefins upon irradiation at 470 nm in the presence of tertiary alkyl amines as sacrificial electron and proton sources. The catalytic hydrogenation of simple olefins served as a test ground to establish this new photo-reactivity of iridium hydrides. Substrates that are very difficult to activate by photoinduced electron transfer were readily hydrogenated, and structure-reactivity relationships established with 12 different olefins are in line with typical HAT reactivity, reflecting the relative stabilities of radical intermediates formed by HAT. Radical clock, H/D isotope labeling, and transient absorption experiments provide further mechanistic insight and corroborate the interpretation of the overall reactivity in terms of photo-triggered hydrogen atom transfer (photo-HAT). The catalytically active species is identified as an Ir(ii) hydride with an IrII-H bond dissociation free energy around 44 kcal mol-1, which is formed after reductive 3MLCT excited-state quenching of the corresponding Ir(iii) hydride, i.e. the actual HAT step occurs on the ground-state potential energy surface. The photo-HAT reactivity presented here represents a conceptually novel approach to photocatalysis with metal complexes, which is fundamentally different from the many prior studies relying on photoinduced electron transfer. This journal is
Preparation of Alkyl Ethers with Diallyltriazinedione-Type Alkylating Agents (ATTACKs-R) Under Acid Catalysis
Fujita, Hikaru,Yamashita, Rina,Fujii, Takanori,Yamada, Kohei,Kitamura, Masanori,Kunishima, Munetaka
, p. 4436 - 4446 (2019/07/03)
Diallyltriazinedione-type acid-catalyzed alkylating agents (ATTACKs-R) with 10 different alkyl groups (R), including benzyl, substituted benzyl, allyl, and methyl groups were synthesized. The palladium-catalyzed intramolecular O-to-N allylic rearrangement of 2,4-bis(allyloxy)-6-chloro-1,3,5-triazine was developed to introduce various alkoxy groups into the N,N′-dialkylated triazinedione skeleton. O-Alkylation of alcohols with ATTACKs-R was carried out in 1,4-dioxane in the presence of 2,6-di-tert-butylpyridinium trifluoromethanesulfonate or trifluoromethanesulfonic acid as a catalyst. Six selected ATTACKs-R bearing benzylic R groups were employed to prepare alkyl ethers from primary, secondary, and tertiary alcohols. The reactions of ATTACKs-R bearing an o-nitro-substituted benzyl group tended to afford low yields. Comparison of four different triazinedione-based benzylating reagents suggested that the N,N′-substituents affected the reactivity.
