128323-04-6Relevant articles and documents
Palladium-Catalyzed para-Selective Alkylation of Electron-Deficient Arenes
Jiao, Zhiwei,Lim, Li Hui,Hirao, Hajime,Zhou, Jianrong Steve
supporting information, p. 6294 - 6298 (2018/05/30)
Intermolecular alkylations of electron-deficient arenes proceed with good para selectivity. Palladium catalysts were used to generate nucleophilic alkyl radicals from alkyl halides, which then directly add onto the arenes. The arene scope and the site of
COMPOUNDS FOR IMPROVING LEARNING AND MEMORY
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Page/Page column 3; 19, (2009/12/23)
The present invention provides a compound of Formula I: (I) and methods for improving memory in a subject by administering a therapeutically effective amount of the compound.
Catalytic enantioselective allyl- and crotylboration of aldehydes using chiral diol·SnCl4 complexes. Optimization, substrate scope and mechanistic investigations
Rauniyar, Vivek,Zhai, Huimin,Hall, Dennis G.
supporting information; experimental part, p. 8481 - 8490 (2009/02/02)
We report a novel class of C2-symmetric chiral diols derived from the hydrobenzoin skeleton. The combination of these diols with SnCl 4 under Yamamoto's concept of Lewis acid assisted Bronsted acidity (LBA catalysis) leads to high levels of asymmetric induction in the allylboration of aldehydes by commercially available allylboronic acid pinacol ester 1a. The corresponding homoallylic alcohol products of synthetically useful aliphatic aldehydes are obtained in excellent yields with up to 98:2 er. This combined acid manifold is also efficient in catalyzing the diastereo- and enantioselective crotylboration of aldehydes, thus providing the propionate units in >95:5 dr and up to 98:2 er. The X-ray crystal structure of the optimal diol·SnCl4 complex, Vivol (4m)·SnCl 4, unambiguously shows the Bronsted acidic character of this LBA catalyst and its highly dissymmetrical environment. Further controls have ruled out a possible boron transesterification mechanism with the chiral diol and point to LBA catalyst-derived activation of the pinacol allylic boronates 1. Due to slow dissociation of the diol·SnCl4 complex, a small excess of diol is required in order to suppress a competing racemic cycle catalyzed by free SnCl4.
Manganese-catalyzed substitution of activated aryl halides (X = Cl, Br and F) and aryl ethers by organomagnesium reagents
Cahiez, Gerard,Lepifre, Franck,Ramiandrasoa, Parfait
, p. 2138 - 2144 (2007/10/03)
In the presence of manganese chloride (10%), Grignard reagents readily react in THF with aryl bromides, chlorides and even fluorides, as well as aryl methyl ethers bearing in the ortho- or para-position an electron withdrawing activating group (CN, CH=NR, oxazoline). Aryl and N- or S- alkylmagnesium halides have been used successfully. The reaction is performed under mild conditions (0 °C to room temperature, 30 minutes to 24 hours) and leads to cross-coupling products in good yields.
