HBr–DMPU: The First Aprotic Organic Solution of Hydrogen Bromide
作者:Zhou Li、Rene Ebule、Jessica Kostyo、Gerald B. Hammond、Bo Xu
DOI:10.1002/chem.201703457
日期:2017.9.18
HBr and DMPU (1,3‐dimethyl‐3,4,5,6‐tetrahydro‐2‐pyrimidinone) form a room‐temperature‐stable complex that provides a mild, effective, and selective hydrobrominating reagent toward alkynes, alkenes, and allenes. HBr–DMPU could also replace other halogenating reagents in the halo‐Prins reaction, ether cleavage, and deoxy‐bromination reactions.
Chloro(phenyl)carbene and diphenylcarbene reacted with cyclopropanonehemiacetals, cyclopropanols, and cyclopropanone cyanohydrins to give 4-phenylbutanoic acid derivatives. The mechanism was explained in terms of a homolytic process that the O-H group of cyclopropanols reacted as a formal H donor with carbenes.
Enantiospecific on-water bromination: a mild and efficient protocol for the preparation of alkyl bromides
作者:Francesco Alletto、Mauro F. A. Adamo
DOI:10.1039/d0gc02855j
日期:——
Herein we report the first example of an on-water enantiospecific synthesis of alkylbromides. This procedure allowed the conversion of secondary activated alkyl sulphides to benzylic alkylbromides, which were obtained in 80–99% yields. The reaction carried out on enantio-pure sulphides provided the corresponding bromides in high yields and enantioselectivity (up to 92% ee; 94% es) at room temperature