Journal of Molecular Catalysis A: Chemical 417 (2016) 10–18 Contents lists available at ScienceDirect Journal of Molecular Catalysis A: Chemical journal homepage: www.elsevier.com/locate/molcata N–H and S–H insertions over Cu(I)-zeolites as heterogeneous catalysts Pipas Saha a , Himchan Jeon b , Pratyush Kumar Mishra a , Hyun-Woo Rhee a,∗ , Ja Hun Kwak b,∗ a Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, South Korea b Department of Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, South Korea a r t i c l e i n f o Article history: Received 19 November 2015 Received in revised form 22 February 2016 Accepted 25 February 2016 Available online 27 February 2016 Keywords: Heterogeneous catalyst Cu(I)-zeolite N–H insertion S–H insertion a b s t r a c t N–H and S–H insertion reactions of -diazoesters into amines and thiols were conducted using various Cu(I)-zeolites, such as zeolite Y, Y USY, ZSM-5, and beta. All the Cu(I)-zeolites successfully catalyzed N–H insertion reactions with high product yields (70–82%) in aqueous solution at room temperature. Interestingly, Cu(I)-USY (Si/Al = 30) showed better activity for both N–H and S–H insertion reactions than Cu(I)-Y (Si/Al = 2.6), even though they have the same structure and the same +1 oxidation state for Cu. X-ray diffraction, transmission electron microscopy, and X-ray photoemission spectroscopy analysis of the fresh and used catalysts revealed that no noticeable change in the zeolite structure, oxidation state of Cu, or sintering of Cu occurred during the reactions. Furthermore, after being recycled four times, the catalysts showed only minor activity decreases, exhibiting conversion rates 70–80% of those of the fresh catalysts, demonstrating their stability under the current reaction conditions. Temperature programmed reduction experiments showed that reduction of Cu + to Cu ◦ occurred at ca. 300 ◦ C over Cu(I)-USY, while it occurred at ca. 800 ◦ C over Cu(I)-Y. The significantly higher activity of Cu(I)-USY than Cu(I)-Y may be due to the more electrophilic Cu centers on Cu(I)-USY, which is highly favorable for ylide formation, and therefore facilitates N–H and S–H insertions. © 2016 Elsevier B.V. All rights reserved. 1. Introduction Carbon–heteroatom bond formation is an important challenge for synthetic chemists because such bonds are present in both nat- ural and man-made molecules [1,2]. Recently, carbenoid-mediated carbon–heteroatom bond formation has become of great interest to the scientific community because carbenoid-based X–H insertions (XHIs), where X = N, O, S, Se, P, or a halogen, are applicable to both small molecules and biomolecules [3–7]. The N–H insertion of - diazocarbonyl compounds into amines using transition metals (Rh, Cu, Fe, Ru, etc.) is very useful for the synthesis of -amino acid derivatives, the basic building blocks of proteins [4,7,8]. Further- more, transition-metal-catalyzed insertions of -diazocarbonyl compounds into the S–H bonds of thiols is an efficient method for the construction of C S bonds, which are present in various natural and synthetic molecules with important biological activities [8,9]. ∗ Corresponding authors. E-mail addresses: rhee@unist.ac.kr (H.-W. Rhee), jhkwak@unist.ac.kr (J.H. Kwak). Much research effort has been focused on developing catalytic reactions based on Cu because it is an abundant and practical alter- native to precious metal catalysts [7]. Furthermore, there have been extensive studies to develop immobilized, reusable Cu catalysts due to their economic and environmental benefits. Therefore, much effort has focused on developing immobilized Cu catalysts on solid- support materials, such as clay [10], silica or silica-alumina [11,12], metal-organic-frameworks [13,14], and polymers [15,16]. Many of these heterogeneous Cu catalysts exhibited similar or better reac- tion performances than those of homogeneous Cu catalysts. Cu(I)-zeolite is a supported catalyst system that, when high- Si/Al-ratio zeolites are employed, exhibits highly stable Cu + [17–22] under aerobic conditions, and they have been employed in vari- ous Cu-catalyzed reactions. For example, Sommer and Pale have extensively studied azide-alkyne cycloadditions [23–25], azome- thine imine cycloadditions [26], multicomponent condensations [27], homocoupling of alkynes [28], and coupling of alkynes with amides [29]. Furthermore, Zaccheria et al. have performed C–H insertion reactions using a heterogeneous Cu/SiO 2 -Al 2 O 3 catalyst [11,12]. Herein, we expand Cu(I)-zeolite-catalyzed reactions to N–H and S–H insertions with -diazoesters (Scheme 1) with high yields http://dx.doi.org/10.1016/j.molcata.2016.02.031 1381-1169/© 2016 Elsevier B.V. All rights reserved.