74889-45-5Relevant academic research and scientific papers
Remarkably Efficient Iridium Catalysts for Directed C(sp2)-H and C(sp3)-H Borylation of Diverse Classes of Substrates
Chattopadhyay, Buddhadeb,Hassan, Mirja Md Mahamudul,Hoque, Md Emdadul
, p. 5022 - 5037 (2021/05/04)
Here we describe the discovery of a new class of C-H borylation catalysts and their use for regioselective C-H borylation of aromatic, heteroaromatic, and aliphatic systems. The new catalysts have Ir-C(thienyl) or Ir-C(furyl) anionic ligands instead of the diamine-type neutral chelating ligands used in the standard C-H borylation conditions. It is reported that the employment of these newly discovered catalysts show excellent reactivity and ortho-selectivity for diverse classes of aromatic substrates with high isolated yields. Moreover, the catalysts proved to be efficient for a wide number of aliphatic substrates for selective C(sp3)-H bond borylations. Heterocyclic molecules are selectively borylated using the inherently elevated reactivity of the C-H bonds. A number of late-stage C-H functionalization have been described using the same catalysts. Furthermore, we show that one of the catalysts could be used even in open air for the C(sp2)-H and C(sp3)-H borylations enabling the method more general. Preliminary mechanistic studies suggest that the active catalytic intermediate is the Ir(bis)boryl complex, and the attached ligand acts as bidentate ligand. Collectively, this study underlines the discovery of new class of C-H borylation catalysts that should find wide application in the context of C-H functionalization chemistry.
Frustrated Lewis Pair Catalyzed Hydrogenation of Amides: Halides as Active Lewis Base in the Metal-Free Hydrogen Activation
Sitte, Nikolai A.,Bursch, Markus,Grimme, Stefan,Paradies, Jan
supporting information, p. 159 - 162 (2019/01/04)
A method for the metal-free reduction of carboxylic amides using oxalyl chloride as an activating agent and hydrogen as the final reductant is introduced. The reaction proceeds via the hydrogen splitting by B(2,6-F2-C6H3)3 in combination with chloride as the Lewis base. Density functional theory calculations support the unprecedented role of halides as active Lewis base components in the frustrated Lewis pair mediated hydrogen activation. The reaction displays broad substrate scope for tertiary benzoic acid amides and α-branched carboxamides.
Amide Effects in C?H Activation: Noncovalent Interactions with L-Shaped Ligand for meta Borylation of Aromatic Amides
Bisht, Ranjana,Hoque, Md Emdadul,Chattopadhyay, Buddhadeb
, p. 15762 - 15766 (2018/11/10)
A new concept for the meta-selective borylation of aromatic amides is described. It has been demonstrated that while esters gave para borylations, amides lead to meta borylations. For achieving high meta selectivity, an L-shaped bifunctional ligand has been employed and engages in an O???K noncovalent interaction with the oxygen atom of the moderately distorted amide carbonyl group. This interaction provides exceptional control for meta C?H activation/borylation.
New heteroaromatic azo compounds based on pyridine, isoxazole, and benzothiazole for efficient and highly selective amidation and mono-N-benzylation of amines under Mitsunobu conditions
Iranpoor, Nasser,Firouzabadi, Habib,Khalili, Dariush
experimental part, p. 923 - 934 (2010/10/01)
4,4′-Azopyridine (2c) is used in conjunction with triphenylphosphine for the efficient conversion of carboxylic acids into amides via Mitsunobu reaction with primary and secondary aliphatic and aromatic amines. The highly selective amidation of only primary aromatic amines with new heterogeneous azo compounds based on benzothiazole 2d and isoxazole 2e is also described. These azo compounds 2c-2e can also be applied for selective mono-N-benzylation of primary aromatic amines. The solid side product heteroaromatic hydrazines obtained under the developed Mitsunobu conditions are easily separated by simple filtration and can be reoxidized to azo compounds for further use.
"Selenium Polonovski Reaction" Using Benzeneselenyl Triflate
Okazaki, Renji,Itoh, Yukinori
, p. 1575 - 1578 (2007/10/02)
Selenoxyammonium salts prepared from tertiary amine N-oxides and benzeneselenyl triflate undergo rearrangement in the presence of triethylamine or DBU to give α-selenoxyamines, which react in situ with an electrophile or nucleophile to afford new secondary or tertiary amine derivatives.
Acyl Halide Induced Cleavage of N-Acylated Aminals
Boehme, Horst,Raude, Edgar
, p. 3421 - 3429 (2007/10/02)
Acyl halides attack N-acylated aminals 6 at the amine nitrogen as well as at the carboxamide group to form either N-halomethyl carboxamides 5 besides N,N-dialkyl carboxamides 11, or diacylamines 12 besides N,N-dialkylmethaneiminium halides 4.Depending on the variation of the substituents on both heteroatoms the cleavage may be directed to follow only one or the other pathway.Of highly synthetic interest is the broadly applicable preparation of methaneiminium salts 4 having bulky substituents on nitrogen by means of cleavage of the corresponding N,N-dialkyl-N'-formyl-N'-methylmethanediamines 6.
