Steric assistance for intramolecular catalysis
نویسندگان
چکیده
منابع مشابه
Control of Modes of Intramolecular Imidazole Catalysis of Ester Hydrolysis by Steric and Electronic Effects
The various mechanisms by which a neighboring imidazolyl nitrogen base (both neutral and anionic) or the conjugate acid imidazolium cation may participate in the hydrolysis of an acetyl ester of a weakly basic or strongly basic phenol have been evaluated (pH 0-13). For this purpose 0-acetyl esters of 2 4 2 ’ and 4‘-hydroxypheny1)imidazoles were prepared (Ia, b, 11, IIIa, b, and IV). Lyate speci...
متن کاملDeciphering DNA-based asymmetric catalysis through intramolecular Friedel-Crafts alkylations.
We describe asymmetric intramolecular Friedel-Crafts alkylations with a DNA-based hybrid catalyst and propose a plausible binding model. This study shows promise for studying relationships between the helical chirality of DNA and enantioselectivity of the chemical reaction.
متن کاملThe role of steric hindrance in the intramolecular oxidative aromatic coupling of pyrrolo[3,2-b]pyrroles.
The presence of steric hindrance triggers different reaction pathways in the intramolecular oxidative aromatic coupling of tetraaryl-pyrrolo[3,2-b]pyrroles and leads to the formation of a fluorene moiety and a new cationic π-system linked together by a spiro carbon atom. Computational studies elegantly rationalized these results. These previously unknown functional dyes emit red light with reas...
متن کاملAcylmethyl(aryl)tellurium(IV,II) derivatives: intramolecular secondary bonding and steric rigidity.
Electrophilic substitution of acylmethanes (methyl ketones), RCOCH3 (R = i-Pr, 1; Et, 2; Me, 3) with aryltellurium trichlorides, ArTeCl3 (Ar = 1-C10H7, Np, A; 2,4,6-Me3C6H2, Mes, B; 4-MeOC6H4, Anisyl, C) under mild conditions affords the corresponding acylmethyl(aryl)tellurium dichlorides (RCOCH2)ArTeCl2. Reduction of the dichlorides, gives tellurides, (i-PrCOCH2)ArTe, 1A-1C, which give the cor...
متن کاملWeakly coordinating counter-ions for highly efficient catalysis of intramolecular hydroamination.
A series of cationic rhodium(I) and iridium(I) complexes of the type [M(L[symbol: see text]L)(C2)]BAr(F)24 (where M = Rh or Ir, L[symbol: see text]L = bis(pyrazol-1-yl)methane (bpm), bis(N-methylimidazol-2-yl)methane (bim) or 1-(2-(diphenylphosphino)ethyl)-3,5-diphenylpyrazole (Ph2PyP), C2 = 1,5-cyclooctadiene (COD) or (CO)2 and BAr(F)24 = tetrakis[3,5-bis(trifluoromethyl)phenyl]borate) were sy...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Biochemical Journal
سال: 1970
ISSN: 0306-3283
DOI: 10.1042/bj1170051pb