Directed Lithiation of N-Benzenesulfonyl-3-bromopyrrole. Electrophile-Controlled Regioselective Functionalization via Dynamic Equilibrium between C-2 and C-5 Lithio Species

作者：Fukuda Tsutomu; Ohta Takeshi; Sudo Ei ichi; Iwao Masatomo^*

来源：Organic Letters, 2010, 12(12): 2734-2737.

DOI：10.1021/ol100810c

Directed lithiation of N-benzenesulfonyl-3-bromopyrrole (1) with LDA in THF at -78 degrees C generated C-2 lithio species 3 selectively. Reactions of 3 with reactive electrophiles produced the corresponding 2-functionalized pyrroles 4. On the other hand, quenching with less reactive electrophiles generated the corresponding 5-substituted pyrroles 5. The latter unusual functionalization at C-5 could be rationalized by dynamic equilibrium between C-2 and C-5 lithio species,

• 出版日期2010-6-18