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The ethylene adducts of copper(I) tris(pyrazolyl)borates, [HB(3,5-(CF 3 ) 2 Pz) 3 ]Cu(C 2 H 4 ), ),5-(C 6 H 5 )Pz) 3 ]Cu(C 2 H 4 ), and [HB(3-(CF 3 )Pz) 3 ]Cu(C 2 H 4 ), have been prepared by reacting the corresponding sodium derivative with CF 3 SO 3 Cu in the presence of ethylene. They were characterized both in the solid state and in solution using 1 H, 13 C, and 19 F NMR and IR spectroscopy and by X-ray crystallography. Solid samples of these nonionic copper complexes featuring fluorinated tris(pyrazolyl)borate ligands display notably high stability toward air oxidation and ethylene loss. The 1 H NMR chemical shifts of the copper(I)-bonded ethylene protons appear in the 4.8-5.2 ppm region. The 13 C signal of copper-coordinated ethylene shows an upfield shift of about 35 ppm, whereas the 1 J C-H shows a minor change (an increase of about 2-5 Hz) compared to the values for free ethylene. X-ray structural data show the presence of pseudo-tetrahedral copper ions and η 2 -bonded ethylene units and relatively unperturbed ethylene C-C distances. The copper adducts [HB(3,5-(CF 3 ) 2 Pz) 3 ]Cu-(C 2 H 4 ) and [HB(3-(CF 3 ),5-(C 6 H 5 )Pz) 3 ]Cu(C 2 H 4 ) are competent aziridination catalysts, readily converting a variety of olefins into the corresponding N-tosyl aziridines with N-tosyl phenyliodinane.

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Silver(I) adducts featuring highly fluorinated tris(pyrazolyl)borate, [HB(3,5-(CF3)2Pz)3]-, catalyze the carbene insertion into carbon−hydrogen bonds of cyclic and acyclic hydrocarbons at room temperature. These silver complexes are more effective than related copper catalysts such as [HB(3,5-(CF3)2Pz)3]Cu(THF) for hydrocarbon activation via this route.

A total synthesis of the putative structure of nagelamide D from imidazole is described. A Stille cross-coupling is used to construct the bis imidazole skeleton, and the pyrrolecarboxamides are introduced via a double Mitsunobu reaction using a pyrrolehydantoin derivative. Discrepancies between the published spectroscopic data and that reported in the literature cast doubts either on the assigned structure or the reported data.The oriodin alkaloids are a growing family of pyrrole-imidazole alkaloids produced by members of the Agelisida, Axinellida, and Halichondrida orders of marine sponges (Figure 1). 1 These natural products range in complexity from the simple monomeric parent system oroidin (1) 2 to the most complex member reported to date, the tetrameric styllisadine A. 3 Formally, these natural products arise from a variety of oxidation and oligomerization pathways of the basic building block oroidin (1) and congeners, but little is known about the details of their biosynthesis. 4, 5 In large part due to the challenging structural problems presented by the dimeric members of this group, we and others have become interested in developing general synthetic approaches to the pyrrole-imidazole alkaloids including ageliferin (2), 6 axinellamine A, 7 palau'amine, 8 and the nagelamides (3-6). 9-11 The original group of nagelamides, is a collection of eight oroidin dimers, which were isolated from an Okinawan marine sponge, Agelas sp. by Kobayashi and coworkers. 9 Subsequently, additional members of this subfamily have emerged which reinforce the structural diversity found in the oroidin natural products. Of the initial collection of natural products, two broad groups of compounds were described

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