A chiral carbene-catalyzed [3+3] annulation of α-bromoenals with 2-aminobenzimidazoles providing pyrimido[1,2-a]benzimidazoles has been described. This protocol features a broad scope and good functional group tolerance. Biological studies indicated that the formed pyrimido[1,2-a]benzimidazole exhibited moderate cytotoxic activity against tumor cells.

中文翻译：

---

NHC对映体选择性催化[3 + 3]与2个氨基苯并咪唑类的α-溴烯醛环状。

已经描述了用2-氨基苯并咪唑手性卡宾催化的α-溴烯醛的[3 + 3]环化，提供了嘧啶并[1,2-a]苯并咪唑。该协议具有广泛的范围和良好的功能组耐受性。生物学研究表明，形成的嘧啶并[1,2-a]苯并咪唑对肿瘤细胞表现出中等的细胞毒活性。