Homoleptic lithium tri‐ and tetraalkyl zincates were reacted with a set of bromopyridines. Efficient and chemoselective bromine–metal exchanges were realized at roomtemperature with a substoichiometric amount of nBu4ZnLi2⋅TMEDA reagent (1/3 equiv; TMEDA=N,N,N′,N′‐tetramethylethylenediamine). This reactivity contrasted with that of tBu4ZnLi2⋅TMEDA, which was inefficient below one equivalent. DFT calculations
Bromine–magnesium exchange using iPrMgCl in THF at roomtemperature on 2-, 3- and 4-bromopyridines allowed the synthesis of various functionalized pyridines. The methodology was successfully used for the synthesis of 4-azaxanthone. Moreover, single exchange reactions observed on 2,6-, 3,5-, 2,3- and 2,5-dibromopyridines, with complete regioselectivity in the case of 2,3- and 2,5-dibromopyridines, afforded
new formal insertion strategy via combination of reductive elimination and oxidative addition sequence was reported, in which the transient N-acyliminium ions formed via hydrocarbonylation function as key intermediates. This strategy has enabled a novel palladium-catalyzed hydrocarbonylative cyclization of azaarene-tethered alkenes or dienes via sequential insertion of a C═C bond, CO, and a C═N bond into