N-Bromosuccinimide promoted and base switchable one pot synthesis of α-imido and α-amino ketones from styrenes
作者:Mahesh H. Shinde、Umesh A. Kshirsagar
DOI:10.1039/c5ob02034d
日期:——
N-Bromosuccinimide (NBS) promoted one pot strategy for the synthesis of α-amino functionalized aryl ketones starting from commercially available styrenes has been developed. NBS participates in multiple tasks, such as bromonium ion formation, oxidation of bromohydrin and providing a nucleophilic nitrogen source. The reaction can easily be switched between α-imido and α-amino ketones by the choice of base
Silver-promoted (radio)fluorination of unsaturated carbamates via a radical process
作者:Bin Yang、Kantapat Chansaenpak、Hongmiao Wu、Lin Zhu、Mengzhe Wang、Zibo Li、Hongjian Lu
DOI:10.1039/c7cc01393k
日期:——
The intramolecular fluorocyclization of unsaturated carbamates proceeds via a cyclization/1,2-(hetero)aryl migration/fluorination cascade involving an unusual radical process, and provides a straightforward access to (radio)fluorinated oxazolidin-2-ones, oxazolidine-2,4-diones and 1,3-oxazinan-2-ones.
An efficient synthetic method for the preparation of multisubstituted furans, thiophenes, and pyrroles using ynolates was developed. This novel formal [4 + 1] annulation by C2-C3 and C3-C4 bond formations includes cycloaddition, cyclization, decarboxylation, and dehydration as key steps.
A number of opticallyactive amino alcohols were synthesized by direct asymmetric transfer hydrogenation of the corresponding amino ketones with good-to-high enantiomeric excesses (up to 95%) and excellent yields (up to 93% ). When the range of substrates was broadened to include α-sulfonamido ketones or α-keto sulfones, the corresponding products were obtained with 100% enantiomeric excesses. The
transition-metal-free direct α-C–H amination of ketones has been developed using commercially available ammonium iodide as the catalyst and sodium percarbonate as the co-oxidant. A wide range of ketone ((hetero)aromatic or nonaromatic ketones) and amine (primary/secondary amines, anilines, or amides) substrates undergo cross-coupling to generate synthetically useful α-amino ketones. The mechanistic studies indicated