Deprotonation of Methyl-Substituted, Five-Membered Aromatic Molecules: A Surprising Case of Mixed Conjugation, Rehybridization, and Induction Contributions

作者：Mo Yirong^*; Ahmed Basil M; Guan Liangyu; Karty Joel; Mezei Gellert

来源：Organic Letters, 2014, 16(17): 4680-4683.

DOI：10.1021/ol502387a

Methyl-substituted, six-membered aromatic molecules are deprotonated to benzylic carbanions, which are stabilized by pi conjugation. In contrast, deprotonation of 3(5)-methylpyrazole (NH protected) occurs at an endocylic CH group. Computational analyses showed that the reduction of pi conjugation in substituted five-membered rings plays a major role, while the reduced bond angles, in addition to the strengthened induction of C-sp(2) versus C-sp(3), further favor the deprotonation of endocydic carbon sites rather than that of the methyl group.

• 出版日期2014-9-5