A cheap metal catalyzed ring expansion/cross-coupling cascade: a new route to functionalized medium-sized and macrolactones

Shuai Liu; Pengchen Ma; Lu Zhang; Shenyu Shen; Hong-Jie Miao; Le Liu; K N Houk; Xin-Hua Duan; Li-Na Guo

doi:10.1039/d2sc06157k

A cheap metal catalyzed ring expansion/cross-coupling cascade: a new route to functionalized medium-sized and macrolactones

Chem Sci. 2023 Apr 17;14(19):5220-5225. doi: 10.1039/d2sc06157k. eCollection 2023 May 17.

Authors

Shuai Liu¹, Pengchen Ma^{1

2}, Lu Zhang¹, Shenyu Shen¹, Hong-Jie Miao¹, Le Liu¹, K N Houk², Xin-Hua Duan¹, Li-Na Guo¹

Affiliations

¹ Department of Chemistry, School of Chemistry, Xi'an Key Laboratory of Sustainable Energy Material Chemistry and Engineering Research Center of Energy Storage Materials and Devices, Ministry of Education, Xi'an Jiaotong University Xi'an 710049 China duanxh@xjtu.edu.cn guoln81@xjtu.edu.cn.
² Department of Chemistry and Biochemistry, University of California Los Angeles California 90095-1569 USA houk@chem.ucla.edu.

Abstract

An efficient alkoxyl radical-triggered ring expansion/cross-coupling cascade was developed under cheap metal catalysis. Through the metal-catalyzed radical relay strategy, a wide range of medium-sized lactones (9-11 membered) and macrolactones (12, 13, 15, 18, and 19-membered) were constructed in moderate to good yields, along with diverse functional groups including CN, N₃, SCN, and X groups installed concurrently. Density functional theory (DFT) calculations revealed that reductive elimination of the cycloalkyl-Cu(iii) species is a more favorable reaction pathway for the cross-coupling step. Based on the results of experiments and DFT, a Cu(i)/Cu(ii)/Cu(iii) catalytic cycle is proposed for this tandem reaction.