Migration du lithium en série pyridinique: double catalyse et reformage. Accès aux dérivés de la bromo-2 lithio-3 pyridine et des bromo-4 halogéno-2 lithio-3 pyridines
Ultrafast Halogen Dance Reactions of Bromoarenes Enabled by Catalytic Potassium Hexamethyldisilazide
作者:Kengo Inoue、Atsunori Mori、Kentaro Okano
DOI:10.1002/chem.202400104
日期:2024.4.22
Lochmann–Schlosser base, a stoichiometric combination of nBuLi and KOtBu, is commonly used as a superbase for deprotonating a wide range of organic compounds. In the present study, we report that catalytic potassium hexamethyldisilazide (KHMDS) exhibits higher catalytic activity than KOtBu for successive bromine–metal exchanges. Accordingly, 1–10 mol% of KHMDS dramatically enhances halogen dance reactions to introduce various electrophiles to bromopyridine, bromoimidazole, bromothiophene, bromofuran, and bromobenzene derivatives with the bromo group translocated from the original position. A dual catalytic cycle is proposed to explain the ultrafast bromine transfer.