13421-13-1Relevant articles and documents
IrIII-Catalyzed Selective ortho-Monoiodination of Benzoic Acids with Unbiased C?H Bonds
Weis, Erik,Johansson, Magnus J.,Martín-Matute, Belén
supporting information, p. 10185 - 10190 (2020/07/31)
An iridium-catalyzed selective ortho-monoiodination of benzoic acids with two equivalent C?H bonds is presented. A wide range of electron-rich and electron-poor substrates undergo the reaction under mild conditions, with >20:1 mono/di selectivity. Importantly, the C?H iodination occurs selectively ortho to the carboxylic acid moiety in substrates bearing competing coordinating directing groups. The reaction is performed at room temperature and no inert atmosphere or exclusion of moisture is required. Mechanistic investigations revealed a substrate-dependent reversible C?H activation/protodemetalation step, a substrate-dependent turnover-limiting step, and the crucial role of the AgI additive in the deactivation of the iodination product towards further reaction.
Synthesis of DIBAC analogues with excellent SPAAC rate constants
Debets, Marjoke F.,Prins, Jasper S.,Merkx, Donny,Van Berkel, Sander S.,Van Delft, Floris L.,Van Hest, Jan C. M.,Rutjes, Floris P. J. T.
supporting information, p. 5031 - 5037 (2014/07/07)
In search for increased reactivity in strain-promoted azide alkyne cycloadditions (SPAAC), the synthesis of new and more reactive cyclooctynes is of pivotal importance. To identify cyclooctynes with enhanced reactivity, without loss of stability, the synthesis and kinetic analysis of new dibenzoazacyclooctyne (DIBAC) analogues were conducted. Starting from iodobenzyl alcohol analogues and ortho-ethynylaniline various substituted dihydrodibenzo[b,f]azocines were produced. Subsequent bromination and elimination proved to be difficult depending on the aromatic substitution pattern, yielding chloro-, bromo-, and methoxy-substituted DIBACs in moderate yield. In the elimination reaction towards nitro- and Br,Cl-DIBAC, the corresponding cyclooctene was obtained instead of the cyclooctyne. Additionally, a dimethoxy-substituted DIBAC analogue was prepared following an alternative route involving light-induced deprotection of a cyclopropenone derivative. In total, four DIBAC analogues were successfully prepared showing excellent rate constants in the SPAAC reaction ranging from 0.45 to 0.9 M-1 s -1, which makes them comparable to the fastest cyclooctynes currently known. This journal is the Partner Organisations 2014.
2-iodoxybenzenesulfonic acid as an extremely active catalyst for the selective oxidation of alcohols to aldehydes, ketones, carboxylic acids, and enones with oxone
Uyanik, Muhammet,Akakura, Matsujiro,Ishihara, Kazuaki
supporting information; experimental part, p. 251 - 262 (2009/06/28)
Electron-donating group-substituted 2-iodoxybenzoic acids (IBXs) such as5-Me-IBX (1g), 5-MeO-IBX (1h), and 4,5-Me2-IBX were superior to IBX 1a as catalysts for the oxidation of alcohols with Oxone (a trad emark of DuPont) under nonaqueous conditions, although Oxone was almost insoluble in most organic solvents. The catalytic oxidation proceeded more rapidly and cleanly in nitromethane. Furthermore, 2-iodoxybenzenesulfonic acid (IBS, 6a) was much more active than modified IBXs. Thus, we established a highly efficient and selective method for the oxidation of primary and secondary alcohols to carbonyl compounds such as aldehydes, carboxylic acids, and ketones with Oxone in nonaqueous nitromethane, acetonitrile, or ethyl acetate in the presence of 0.05-5molpercentof 6a, which was generated in situ from 2-iodobenzenesulfonic acid (7a) or its sodium salt. Cycloalkanones could be further oxidized to α,β- cycloalkenones or lactones by controlling the amounts of Oxone under the same conditions as above. When Oxone was used under nonaqueous conditions, Oxone wastes could be removed by simple filtration. Based on theoretical calculations, we considered that the relatively ionic character of the intramolecular hypervalent iodine-OSO2 bond of IBS might lower the twisting barrier of the alkoxyperiodinane intermediate 16.
