103-63-9Relevant articles and documents
Unusually Long Lifetimes of the Singlet Derived from 4-Azido-2,3,5,6-tetrafluorobenzamides
Marcinek, Andrzej,Platz, Matthew S.,Chan, Stephen Y.,Floresca, Rey,Rajagopalan, Krishnan,et al.
, p. 412 - 419 (1994)
Laser flash photolysis (308 nm, 20 ns, 150 mJ) of 4-azido-2,3,5,6-tetrafluorobenzamides, esters, and thioesters generate singlet nitrenes which can be intercepted with pyridine to produce strongly absorbing ylides.It was possible to resolve the rate of formation of the ylides as a function of pyridine concentration.This has lad to direct measurements of the absolute rate constants of (a) the reaction of the nitrene with pyridine, (b) ring expansion of the nitrene to a ketenimine, and (c) singlet to triplet nitrene intersystem crossing.
-
Walling,Kharasch,Mayo
, p. 2693,2964 (1939)
-
Selective carboxylation of reactive benzylic C–H bonds by a hypervalent iodine(III)/inorganic bromide oxidation system
Dohi, Toshifumi,Iwasaki, Kosuke,Kita, Yasuyuki,Morimoto, Koji,Tsunoda, Yusuke,Ueda, Shohei
, p. 1087 - 1094 (2018)
An oxidation system comprising phenyliodine(III) diacetate (PIDA) and iodosobenzene with inorganic bromide, i.e., sodium bromide, in an organic solvent led to the direct introduction of carboxylic acids into benzylic C–H bonds under mild conditions. The unique radical species, generated by the homolytic cleavage of the labile I(III)–Br bond of the in situ-formed bromo-λ3-iodane, initiated benzylic carboxylation with a high degree of selectivity for the secondary benzylic position.
-
Kharasch,Weinhouse
, p. 209,227 (1936)
-
Approach to Comparing the Functional Group Tolerance of Reactions
Gensch, Tobias,Teders, Michael,Glorius, Frank
, p. 9154 - 9159 (2017)
Herein, we describe an approach to quantifying and comparing functional group (FG) tolerance of synthetic reactions. Additive-based reaction screening is utilized as a tool for the objective comparison of reaction conditions as demonstrated in four case studies. This contributes to an understanding of factors limiting a reaction's FG tolerance and the identification of truly mild reactions.
-
Wiley et al.
, p. 964 (1964)
-
Scalable anti-Markovnikov hydrobromination of aliphatic and aromatic olefins
Galli, Marzia,Fletcher, Catherine J.,Del Pozo, Marc,Goldup, Stephen M.
, p. 5622 - 5626 (2016)
To improve access to a key synthetic intermediate we targeted a direct hydrobromination-Negishi route. Unsurprisingly, the anti-Markovnikov addition of HBr to estragole in the presence of AIBN proved successful. However, even in the absence of an added initiator, anti-Markovnikov addition was observed. Re-examination of early reports revealed that selective Markovnikov addition, often simply termed "normal" addition, is not always observed with HBr unless air is excluded, leading to the rediscovery of a reproducible and scalable initiator-free protocol.
-
Horne,Shriner
, p. 4652 (1933)
-
Regio- and stereoselective synthesis of bromoalkenes by homolytic hydrobromination of alkynes with hydrogen bromide
Kumaki, Wataru,Kinoshita, Hidenori,Miura, Katsukiyo
supporting information, (2022/03/07)
Homolytic hydrobromination of terminal and internal alkynes with a commercially available solution of hydrogen bromide in acetic acid has been investigated for regio- and stereoselective synthesis of bromoalkenes. Under an aerobic atmosphere at room temperature, the reaction of ethynylarenes with a small excess of HBr efficiently gave (2-bromoethenyl)arenes with good to high E-selectivity. (Alk-1-ynyl)arenes, or internal alkynes bearing both phenyl and alkyl groups at the sp-carbons also underwent the air-initiated hydrobromination to exhibit high Z-selectivity under kinetic conditions using a half equivalent of HBr.
A General Approach to Deboronative Radical Chain Reactions with Pinacol Alkylboronic Esters
André-Joyaux, Emy,Kuzovlev, Andrey,Renaud, Philippe,Tappin, Nicholas D. C.
, p. 13859 - 13864 (2020/06/10)
The generation of carbon-centered radicals from air-sensitive organoboron compounds through nucleohomolytic substitution at boron is a general method to generate non-functionalized and functionalized radicals. Due to their reduced Lewis acidity, alkylboronic pinacol esters are not suitable substrates. We report their in situ conversion into alkylboronic catechol esters by boron-transesterification with a substoichiometric amount of catechol methyl borate combined with an array of radical chain processes. This simple one-pot radical-chain deboronative method enables the conversion of pinacol boronic esters into iodides, bromides, chlorides, and thioethers. The process is also suitable the formation of nitriles and allylated compounds through C?C bond formation using sulfonyl radical traps. The power of combining radical and classical boron chemistry is illustrated with a modular 5-membered ring formation using a combination of three-component coupling and protodeboronative cyclization.
