Condition‐Controlled Selective Synthesis of <scp>CF<sub>3</sub></scp>‐Chromene and <scp>CF<sub>3</sub></scp>‐Benzofuran from <i>N</i>‐Phenoxyacetamide and <scp>CF<sub>3</sub></scp>‐Ynone
Huihang Hou, Shengnan Yan, Yuanshuang Xu, Chunhua Ma, Xinying Zhang, Xuesen Fan
Abstract
Comprehensive Summary Presented herein is a condition‐controlled selective synthesis of CF 3 ‐chromene and CF 3 ‐benzofuran based on the reaction of N ‐phenoxyacetamide and CF 3 ‐ynone. When the reaction is carried out in MeOH under the catalysis of Rh(III), CF 3 ‐chromene is formed via C—H metalation‐initiated alkenylation, acetamide group migration and intramolecular oxo ‐nucleophilic addition. On the other hand, when the reaction is run in DMSO under the promotion of CsOAc, CF 3 ‐benzofuran is generated via aza ‐Michael addition‐initiated [3,3]‐σ rearrangement, intramolecular oxo ‐nucleophilic addition and water elimination. To our knowledge, this is the first report on the selective construction of chromene or benzofuran scaffold along with introduction of a CF 3 unit from the same starting materials. The methodology was scalable and the products could be readily transformed into other valuable products. Moreover, the products thus obtained possess decent anticancer activity.