Optional synthesis of 2- OR 5-substituted 3-bromopyrroles via bromine-lithium exchange of N-benzenesulfonyl-2,4-dibromopyrrole
The regioselective bromine-lithium exchange of N-benzenesulfonyl-2,4- dibromopyrrole (6) with n-BuLi followed by treatment with various electrophiles gave 5-substituted 3-bromopyrroles (5) in excellent yields. In contrast, the sequential treatment of 6 wi
Fukuda, Tsutomu,Iwao, Masatomo
p. 1261 - 1273
(2013/08/23)
Directed lithiation of N -benzenesulfonyl-3-bromopyrrole. Electrophile-controlled regioselective functionalization via dynamic equilibrium between C-2 and C-5 lithio species
(Figure presented) Directed lithiation of N-benzenesulfonyl-3-bromopyrrole (1) with LDA in THF at -78 °C generated C-2 lithio species 3 selectively. Reactions of 3 with reactive electrophiles produced the corresponding 2-functionalized pyrroles 4. On the