FeCl₃ · 6H₂O-Catalyzed Bromocyclization to Access Functionalized Dihydropyrans

Abstract

The FeCl₃ · 6H₂O-catalyzed bromocyclization of polysubstituted 2,5-hexadiene-1-ol provides a simple method to synthesize functionalized 2,3,4,6-tetrasubstituted 5,6-dihydro-2H-pyrans.

Keywords:

• Bromocyclization
• dihydropyrans
• 2,5-hexadiene-1-ol
• iron(III) catalyst

ACKNOWLEDGMENTS

The authors are grateful to the National Natural Science Foundation of China (Nos. 20672001 and 20772001) for financial support of this work. We are also grateful to Prof. Jiping Hu, Hongtao Zhang, and Yun Wei for their helpful assistance.

Notes

^a Isolated yield based on 1a.

^b Determined by ¹H NMR spectra of the crude reaction mixture.

^c The reactions were conducted at reflux temperature.

^d 10 mol% FeCl₃ · 6H₂O was used.

^a Isolated yield based on 1.

^b Determined by ¹H NMR spectra of the crude reaction mixture.