Metal-/solvent-free oxidative [4+2]/[3+2] annulation of 2-ethynylbenzaldehydes with arylalkenes: facile synthesis of benzo[a]fluoren-5-ones

作者：Wang, Cheng-Yong^*; Yu, Jiang-Xi; Liu, Bang; Zhang, Fu-Xing; Wang, Zhi-Qiang^*; Hu, Qin-Yu; Xu, Zhi-Feng^*; Li, Jin-Heng^*

来源：Organic Chemistry Frontiers, 2022, 9(11): 2939-2943.

DOI：10.1039/d1qo01888d

• CATALYZED CASCADE ANNULATION
• ALPHA-BROMOCARBONYLS
• N-ARYLPROPIOLAMIDES
• RADICAL-ADDITION
• VINYL ACIDS
• ALKENES
• ACYLATION
• ALDEHYDES
• ALKYNES
• BICYCLIZATION

We report here a DTBP-mediated oxidative [4 + 2]/[3 + 2] annulation between 2-alkynylbenzaldehydes and terminal arylalkenes enabled by aldehyde C(sp(2))-H functionalization for assembling a range of benzo[a]fluoren-5-ones with high step-economy, simple operation under metal-/solvent-free conditions and excellent functional group tolerance. This method is initiated from 2-alkynylbenzaldehyde reaction partners and provides a useful new strategy to construct complex benzo[a]fluoren-5-one scaffolds compared to existing protocols initiating from alkene reaction partners.

• 单位
  南昌航空大学; 衡阳师范学院