In(III)/PhCO2H Binary Acid Catalyzed Tandem [2 + 2] Cycloaddition and Nazarov Reaction between Alkynes and Acetals
Lihui Zhu, Zhi-Guo Xi, Jian Lv and Sanzhong Luo*
*CAS Key Laboratory for Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China, Email: luosziccas.ac.cn
L. Zhu, Z.-G. Xi, J. Lv, S. Luo, Org. Lett., 2013, 15, 4496-4499.
DOI: 10.1021/ol4020464 (free Supporting Information)
The combination of In(OTf)3 and benzoic acid synergistically promotes the coupling of alkynes and acetals to form 2,3-disubstituted indanones in excellent yield and diastereoselectivity via a tandem [2 + 2] cycloaddition and Nazarov reaction.
see article for more examples