824-47-5Relevant academic research and scientific papers
Chemoselective Homologation-Deoxygenation Strategy Enabling the Direct Conversion of Carbonyls into (n+1)-Halomethyl-Alkanes
Citarella, Andrea,Holzer, Wolfgang,Ielo, Laura,Langer, Thierry,Miele, Margherita,Pace, Vittorio,Urban, Ernst,Zehl, Martin
supporting information, p. 7629 - 7634 (2020/10/12)
The sequential installation of a carbenoid and a hydride into a carbonyl, furnishing halomethyl alkyl derivatives, is reported. Despite the employment of carbenoids as nucleophiles in reactions with carbon-centered electrophiles, sp3-type alkyl halides remain elusive materials for selective one-carbon homologations. Our tactic levers on using carbonyls as starting materials and enables uniformly high yields and chemocontrol. The tactic is flexible and is not limited to carbenoids. Also, diverse carbanion-like species can act as nucleophiles, thus making it of general applicability.
Homologation Strategy for the Generation of 1-Chloroalkyl Radicals from Organoboranes
Xu, Gong,Lüthy, Monique,Habegger, Jacqueline,Renaud, Philippe
, p. 1506 - 1519 (2016/03/01)
The generation of 1-bromo and 1-chloroalkyl radicals from organoboranes has been investigated. The direct approach involving the hydroboration of halogenated alkenes is impeded by partial dehalogenation taking place during the hydroboration process. An indirect method involving the generation of B-(1-chloroalkyl)catecholborane by homologation of B-alkylcatecholborane with dichloromethyllithium was developed. A reaction sequence involving a hydroboration reaction, a Matteson homologation, and a radical allylation process has been performed as a one-pot process that takes advantage of three different reactivities of organoboron species. Starting from styrene derivatives, it was possible to prepare B-(1-chloro-2-arylpropyl)catecholboranes that are excellent precursors to 1-chloro-2-arylpropyl radicals. A concise approach for the synthesis of an optically active α-methylene-γ-lactone from p-chlorostyrene has been developed on the basis of a two-step sequence involving an enantioselective hydroboration-homologation-cyclization reaction followed by a hydrolysis-lactonization process. (Chemical Equation Presented).
A Visible-Light-Induced α-H Chlorination of Alkylarenes with Inorganic Chloride under NanoAg@AgCl
Liu, Shouxin,Zhang, Qi,Li, Huiying,Yang, Yihua,Tian, Xia,Whiting, Andrew
supporting information, p. 9671 - 9675 (2015/06/30)
An efficient, photocatalytic chlorination of alkylarene α-H groups using NaCl/HCl as a chlorine source has been developed, which involves a radical mechanism under visible-light (including sunlight) conditions. A chlorine radical is proposed to be formed by an electron transfer from chloride ion to O2 in air through the bandgap hole of the semiconductor AgCl. The chlorination protocol is characterized by its use of natural sunlight or other visible light, mild conditions, cheap source of chlorine, green solvent, and high selectivity. The yield of benzylchloride is 95 % with a toluene conversion as high as 40 %, which rivals traditional chlorination methods.
The direct anti-Markovnikov addition of mineral acids to styrenes
Wilger, Dale J.,Grandjean, Jean-Marc M.,Lammert, Taylor R.,Nicewicz, David A.
, p. 720 - 726 (2014/08/05)
The direct anti-Markovnikov addition of strong Bronsted acids to alkenes remains an unsolved problem in synthetic chemistry. Here, we report an efficient organic photoredox catalyst system for the addition of HCl, HF and also phosphoric and sulfonic acids to alkenes, with complete regioselectivity. These transformations were developed using a photoredox catalyst in conjunction with a redox-active hydrogen atom donor. The nucleophile counterion plays a critical role by ensuring high reactivity, with 2,6-lutidinium salts typically furnishing the best results. The nature of the redox-active hydrogen atom donor is also consequential, with 4-methoxythiophenol providing the best reactivity when 2,6-lutidinium salts are used. A novel acridinium sensitizer provides enhanced reactivity within several of the more challenging reaction manifolds. This Article demonstrates how nucleophilic addition reactions mediated by photoredox catalysis can change the way electrophilic and homofugal precursors are constructed.
Triphosgene-amine base promoted chlorination of unactivated aliphatic alcohols
Villalpando, Andres,Ayala, Caitlan E.,Watson, Christopher B.,Kartika, Rendy
, p. 3989 - 3996 (2013/06/04)
Unactivated α-branched primary and secondary aliphatic alcohols have been successfully transformed into their corresponding alkyl chlorides in high yields upon treatment with a mixture of triphosgene and pyridine in dichloromethane at reflux. These mild chlorination conditions are high yielding, stereospecific, and well tolerated by numerous sensitive functionalities. Furthermore, no nuisance waste products are generated in the course of the reactions.
Interpretation of retention indices in gas chromatography for establishing structures of isomeric products of alkylarenes radical chlorination
Zenkevich
, p. 270 - 280 (2007/10/03)
By an example of previously uncharacterized products obtained by alkylarenes radical chlorination was demonstrated that combination of various interpretation methods applied to the retention indices (RI) in the gas chromatography on the standard nonpolar phases (comparison of RI of products and initial compounds, characteristics of succession of the chromatographic elution of the structural isomers with the use of estimation of molecular dynamic parameters, application of the additive schemes to RI calculation, and using of structural analogy CH3?Cl for testing the results obtained) permitted unambiguous identification of the structure even without data of mass spectrometry.
Conformational interactions between a phenyl ring and a side-chain halide substituent: a 1H NMR and molecular mechanics study of some 2-aryl-1-halopropanes
Cook, Michael J.,Howe, Trevor J.
, p. 957 - 965 (2007/10/02)
1H NMR data are reported for a series of 2-aryl-1-halopropanes.Vicinal coupling constants in the CH2-CH-fragment show that the rotamer populations about the C-C bond are sensitive to para substituents.The ratio of anti-gauche aryl/halide conformers is greatest when the para substituent is the electron-donating ethyl group and least when it is the strongly electron-withdrawing nitro group.This points to a non-steric conformational interaction involving the ring and the sidechain heteroatom.Comparison of the empirical results with conformational preferences predictedfrom molecular mechanics calculations using the COSMIC force field suggests that the interaction serves to enhance the population of the anti arrangement.
RELATIONSHIP GOVERNING THE ALKYLATION OF AROMATIC HYDROCARBONS WITH ALLYL CHLORIDE AND BROMIDE IN THE PRESENCE OF SULFURIC ACID
Magerramov, M. N.
, p. 1485 - 1488 (2007/10/02)
The kinetic relationships governing the alkylation of aromatic hydrocarbons by allyl chloride and allyl bromide in the presence of sulfuric acid were studied.It was established that the reactivity of the aromatic hydrocarbons varies in relation to the "activity" of the allyl halides in the order allyl chloride > allyl bromide > propylene.
