Photoredox‐Catalyzed Cyclobutane Synthesis by a Deboronative Radical Addition–Polar Cyclization Cascade
作者:Chao Shu、Adam Noble、Varinder K. Aggarwal
DOI:10.1002/anie.201813917
日期:2019.3.18
single‐electron transfer induced deboronative radicaladdition to an electron‐deficient alkene followed by single‐electron reduction and polar 4‐exo‐tet cyclization with a pendant alkyl halide. Key to the success of the methodology was the use of easily oxidizable arylboronate complexes. Structurally diverse cyclobutanes are shown to be conveniently prepared from readily available alkylboronic esters and
Intramolecular Phenyl Transfer from a Boronate to Lithium in the Gas Phase Reveals Crucial Role of Solvation in Transmetalations
作者:Finn Kraft、Konrad Koszinowski
DOI:10.1002/chem.202303653
日期:——
electronegativity difference of the involved metals/metalloids. A combination of gas-phase and solution experiments, together with quantum chemical calculations, reveals the crucial role of solvation in the transmetalation from lithium to boron. Only in the presence of solvent molecules, the reaction proceeds in the expected direction, whereas the formation of the organolithiumcompound is favored in the gas phase
Towards Iron-Catalysed Suzuki Biaryl Cross-Coupling: Unusual Reactivity of 2-Halobenzyl Halides
作者:Robin Bedford、Timothy Gallagher、Dominic Pye、William Savage
DOI:10.1055/s-0034-1380135
日期:——
The reaction of 2-halobenzyl halides with the borate anion Li[(Ph)(t-Bu)Bpin] leads not only to the expected arylation at the benzyl position, but also to some Suzuki biaryl cross-coupling. Preliminary mechanistic investigations hint towards the intermediacy of benzyl iron intermediates that can either: (a) directly cross-couple with the aryl boron reagent to give observed monoarylated species, or (b) undergo oxidative addition of the aryl halide to generate the diarylated species on reaction with the boron-based nucleophile.