Ensembles of Metal Triflate Additives in Gold(I)-Catalyzed Formal [2 + 2 + 2] Cycloaddition of Carbonyls with Activated Terminal Alkynes: One-Pot Synthesis of 2 H-Pyrans

Dan-Bi Sung; Jong Seok Lee

doi:10.1021/acs.orglett.3c02536

Ensembles of Metal Triflate Additives in Gold(I)-Catalyzed Formal [2 + 2 + 2] Cycloaddition of Carbonyls with Activated Terminal Alkynes: One-Pot Synthesis of 2 H-Pyrans

Org Lett. 2023 Oct 6;25(39):7110-7114. doi: 10.1021/acs.orglett.3c02536. Epub 2023 Sep 8.

Authors

Dan-Bi Sung¹, Jong Seok Lee^{1

2}

Affiliations

¹ Marine Natural Products Chemistry Laboratory, Korea Institute of Ocean Science and Technology, Busan 49111, Republic of Korea.
² Department of Marine Technology & Convergence Engineering, Korea University of Science and Technology, Daejeon 34113, Republic of Korea.

PMID: 37682002
DOI: 10.1021/acs.orglett.3c02536

Abstract

Herein, we describe a gold(I)-catalyzed intermolecular formal [2 + 2 + 2] cycloaddition of a carbonyl compound and a propiolate. A series of highly substituted 2H-pyrans are accessed regioselectively from acyclic and cyclic ketones and aldehydes with various substituted propiolates using Ph₃PAuCl (0.1-1 mol %) with two distinct metal triflate additives [0.75-7.5 mol %; In(OTf)₃/Cu(OTf)₂ for ketones, Bi(OTf)₃/Hf(OTf)₄ for aldehydes]. This method should provide an opportunity for further development of synthetic access to other heterocyclic compounds.