573-43-3Relevant articles and documents
Ring Closing Metathesis Approach for the Synthesis of o-Terphenyl Derivatives
Karmakar, Shilpi,Mandal, Tirtha,Dash, Jyotirmayee
, p. 5916 - 5924 (2019/08/21)
A linear synthesis of o-terphenyl derivatives has been delineated using ring closing metathesis (RCM) as the key step. In this approach, benzil derivatives upon allyl Grignard addition provides diphenyl-1,2-diallyl dihydroxy derivatives which undergo ring closing metathesis to afford tetrahydro terphenyl derivatives. Aromatization-driven dehydration then leads to a diverse set of electron rich and electron deficient o-terphenyls. Furthermore, oxidative coupling of electron rich o-terphenyls provides the corresponding triphenylene derivatives.
Base-Free Asymmetric Transfer Hydrogenation of 1,2-Di- and Monoketones Catalyzed by a (NH)2P2-Macrocyclic Iron(II) Hydride
De Luca, Lorena,Mezzetti, Antonio
supporting information, p. 11949 - 11953 (2017/09/20)
The hydride isonitrile complex [FeH(CNCEt3)(1 a)]BF4 (2) containing a chiral P2(NH)2 macrocycle (1 a), in the presence of 2-propanol as hydrogen donor, catalyzes the base-free asymmetric transfer hydrogenation (ATH) of prostereogenic ketones to alcohols and the hemihydrogenation of benzils to benzoins, which contain a base-labile stereocenter. Benzoins are formed in up to 83 % isolated yield with enantioselectivity reaching 95 % ee. Ketones give the same enantioselectivity observed with the parent catalytic system [Fe(CNCEt3)2(1 a)] (3 a) that operates with added NaOtBu.
Dendrimer-like core cross-linked micelle stabilized ultra-small gold nanoclusters as a robust catalyst for aerobic oxidation of α-hydroxy ketones in water
Yu, Yangyang,Lin, Chenlu,Li, Bing,Zhao, Pengxiang,Zhang, Shiyong
, p. 3647 - 3655 (2016/07/06)
As one of the most general and promising stabilizers, dendrimers have been widely used to prepare ultra-small gold nanoclusters. However, the complex synthesis of dendrimers hinders the further application of protected nanoclusters. Here we report a facile strategy to prepare an alternative material via core cross-linking of self-assembled micelles. The resulting dendrimer-like core cross-linked micelles (DCCMs) retain the main characteristics of dendrimers and avoid complex chemical synthesis. As expected, the DCCMs could easily encapsulate gold nanoparticles within their cores. The ultra-small clusters of Au5 were prepared without the participation of external reductants. Importantly, the DCCM stabilized noble gold clusters furnish excellent catalytic activity and perfect reusability for aerobic oxidation of α-hydroxy ketones in water. Only in open air the oxidation could be repeated up to 48 times with negligible turn-over frequency change. The total turnover number (TON) of the reaction reached unexpectedly >48 000, the highest TON for metal catalysed oxidation of hydroxy ketones so far. The further mechanism study hints that the carboxylic group of substrates might be involved in the catalytic process. The simple catalyst preparation, the environmentally benign reaction conditions, and the excellent catalytic performance and durability make the novel DCCM protected gold nanocluster a green catalyst.
