587-03-1Relevant articles and documents
Photochemical substitution of polyhalogenothiophene and halogenothiazole derivatives
D'Auria, Maurizio,Distefano, Claudio,D'Onofrio, Franco,Mauriello, Giacomo,Racioppi, Rocco
, p. 3513 - 3518 (2000)
The irradiation of 2,3-diodo-5-nitrothiophene in the presence of aromatic and heteroaromatic compounds gave the corresponding 2-aryl derivatives in high yields. The irradiation of 2,4-diiodo-5-nitrothiophene under the same conditions gave the corresponding 2-aryl derivatives in low yields. The observed difference in the reactivity can be explained on the basis of the hypothesis that the homolytic cleavage of the carbon-iodine bond occurred in a π,π* triplet state. Computational results showed that the lowest triplet state of the 2,3-diiodo isomer is π,π*, while that of the 2,4-isomer is π,π*. The irradiation of 2-bromo-5-nitrothiazole in the presence of benzene or indene gave the corresponding 2-bromo-5-arylthiazole. This behaviour can be explained by considering that the lowest excited triplet state cannot allow the cleavage of the carbon-bromine bond thus electron transfer occurs and leads to the substitution of the nitro group. The photochemical substitution reactions on 2,3-diiodo-5-nitrothiophene can be carried out in large scale using a new flow reactor using a PFTE pipe.
Chemoselective (Hetero)Arene Electroreduction Enabled by Rapid Alternating Polarity
Hayashi, Kyohei,Griffin, Jeremy,Harper, Kaid C.,Kawamata, Yu,Baran, Phil S.
, p. 5762 - 5768 (2022/04/15)
Conventional chemical and even electrochemical Birch-type reductions suffer from a lack of chemoselectivity due to a reliance on alkali metals or harshly reducing conditions. This study reveals that a simpler avenue is available for such reductions by simply altering the waveform of current delivery, namely rapid alternating polarity (rAP). The developed method solves these issues, proceeding in a protic solvent, and can be easily scaled up without any metal additives or stringently anhydrous conditions.
Sodium Aminodiboranate, a New Reagent for Chemoselective Reduction of Aldehydes and Ketones to Alcohols
Wang, Jin,Guo, Yu,Li, Shouhu,Chen, Xuenian
supporting information, p. 1104 - 1108 (2021/05/25)
Sodium aminodiboranate (NaNH 2(BH 3) 2, NaADBH) is a new member of the old borane family, which exhibits superior performance in chemoselective reduction. Experimental results show that NaADBH can rapidly reduce aldehydes and ketones to the corresponding alcohols in high efficiency and selectivity under mild conditions. There are little steric and electronic effects on this reduction.
Reaction of Diisobutylaluminum Borohydride, a Binary Hydride, with Selected Organic Compounds Containing Representative Functional Groups
Amberchan, Gabriella,Snelling, Rachel A.,Moya, Enrique,Landi, Madison,Lutz, Kyle,Gatihi, Roxanne,Singaram, Bakthan
supporting information, p. 6207 - 6227 (2021/05/06)
The binary hydride, diisobutylaluminum borohydride [(iBu)2AlBH4], synthesized from diisobutylaluminum hydride (DIBAL) and borane dimethyl sulfide (BMS) has shown great potential in reducing a variety of organic functional groups. This unique binary hydride, (iBu)2AlBH4, is readily synthesized, versatile, and simple to use. Aldehydes, ketones, esters, and epoxides are reduced very fast to the corresponding alcohols in essentially quantitative yields. This binary hydride can reduce tertiary amides rapidly to the corresponding amines at 25 °C in an efficient manner. Furthermore, nitriles are converted into the corresponding amines in essentially quantitative yields. These reactions occur under ambient conditions and are completed in an hour or less. The reduction products are isolated through a simple acid-base extraction and without the use of column chromatography. Further investigation showed that (iBu)2AlBH4 has the potential to be a selective hydride donor as shown through a series of competitive reactions. Similarities and differences between (iBu)2AlBH4, DIBAL, and BMS are discussed.