52657-84-8Relevant articles and documents
Regio/site-selective alkylation of substrates containing a: Cis -, 1,2- or 1,3-diol with ferric chloride and dipivaloylmethane as the catalytic system
Lv, Jian,Liu, Yu,Zhu, Jia-Jia,Zou, Dapeng,Dong, Hai
supporting information, p. 1139 - 1144 (2020/03/11)
In this study, we reported the regio/site-selective alkylation of substrates containing a cis-, 1,2- or 1,3-diol with FeCl3 as a key catalyst. A catalytic system consisting of FeCl3 (0.01-0.1 equiv.) and dipivaloylmethane (FeCl3/dipivaloylmethane = 1/2) was used to catalyze the alkylation in the presence of a base. The produced selectivities and isolated yields were similar to those obtained by methods using the same amount of FeL3 (L = acylacetone ligand) as the catalyst in most cases. The previously reported FeL3 catalysts for alkylation are not commercially available and have to be synthesized prior to use. In contrast, FeCl3 and dipivaloylmethane (Hdipm) are very common and inexpensive nontoxic reagents in the lab, thereby making the method much greener and easier to handle. Mechanism studies confirmed for the first time that FeCl3 initially reacts with two equivalents of Hdipm to form [Fe(dipm)3] in the presence of a base in acetonitrile, followed by the formation of a five or six-membered ring intermediate between [Fe(dipm)3] and two hydroxyl groups of the substrate. A subsequent reaction between the cyclic intermediate and the alkylating agent results in selective alkylation of the substrate.
Intramolecular OH...Fluorine Hydrogen Bonding in Saturated, Acyclic Fluorohydrins: The γ-Fluoropropanol Motif
Linclau, Bruno,Peron, Florent,Bogdan, Elena,Wells, Neil,Wang, Zhong,Compain, Guillaume,Fontenelle, Clement Q.,Galland, Nicolas,Le Questel, Jean-Yves,Graton, Jér?me
, p. 17808 - 17816 (2015/12/08)
Fluorination is commonly exercised in compound property optimization. However, the influence of fluorination on hydrogen-bond (HB) properties of adjacent functional groups, as well as the HB-accepting capacity of fluorine itself, is still not completely understood. Although the formation of OH...F intramolecular HBs (IMHBs) has been established for conformationally restricted fluorohydrins, such interaction in flexible compounds remained questionable. Herein is demonstrated for the first time - and in contrast to earlier reports - the occurrence of OH...F IMHBs in acyclic saturated γ-fluorohydrins, even for the parent 3-fluoropropan-1-ol. The relative stereochemistry is shown to have a crucial influence on the corresponding h1JOH...F values, as illustrated by syn- and anti-4-fluoropentan-2-ol (6.6 and 1.9 Hz). The magnitude of OH...F IMHBs and their strong dependence on the overall molecular conformational profile, fluorination motif, and alkyl substitution level, is rationalized by quantum chemical calculations. For a given alkyl chain, the "rule of shielding" applies to OH...F IMHB energies. Surprisingly, the predicted OH...F IMHB energies are only moderately weaker than these of the corresponding OH...OMe. These results provide new insights of the impact of fluorination of aliphatic alcohols, with attractive perspectives for rational drug design.
Total synthesis of the proposed structure of the anthrapyran metabolite δ-indomycinone
Tietze, Lutz F.,Singidi, Ramakrishna Reddy,Gericke, Kersten M.
, p. 9939 - 9947 (2008/09/18)
The first total synthesis of the proposed structure of δ-indomycinone has been accomplished. The key steps involve the Diels-Alder reaction of a bromonaphthoquinone (6) and 1-methoxy-3-methyl-1-trimethylsiloxy-1,3-butadiene (7) to access the anthraquinone
