Group Transfer from Nickel Imido, Phosphinidene, and Carbene Complexes to Ethylene with Formation of Aziridine, Phosphirane, and Cyclopropane Products

Abstract

The reactions of nickel complexes bearing terminal imido, phosphinidene, and carbene ligands with ethylene are reported. In all three cases, corresponding three-membered rings, aziridine, phosphirane, and cyclopropane, were produced in moderate to excellent yields. NMR spectra of the phosphinidene (dtbpe)Ni=P(dmp) reaction with ethylene show a [2+2] cycloaddition adduct before phosphirane formation. A labeling study with trans-ethylene-d2 shows formation of aziridine and phosphirane proceeds with net retention of relative stereochemistry.

Trapping of an NiII Sulfide by a CoI Fulvene Complex

“…5,6 A number of late transition metal carbene (CR 2 2-), nitrene (NR 2-), nitride (N 3-), and phosphinidene (PR 2-) complexes have also been reported in recent years. [7][8][9][10][11][12][13][14][15][16][17][18] While a few of these complexes have been isolated, they tend to be extremely reactive, and often can only be observed spectroscopically. [19][20][21][22] Nonetheless, it is clear that synthetic chemists are now beginning to identify the combination of ligand requirements and synthetic procedures that can successfully generate late-metal ligand multiple bonds.…”

C–H Functionalization Reactivity of a Nickel–Imide

“…4 Later, Cenini and co-workers isolated the N-aryl analogue (porphyrin)Ru(NAr F ) 2 (Ar F = 3,5-(CF 3 ) 2 C 6 H 3 ) that reacts with C−H bonds of modest strength such as the allylic C−H bond of cyclohexene. 12 Nickel imides have played key roles in the renaissance of late metal imido chemistry 1 ignited by the 2001 report of the three coordinate terminal imide (dtbpe)NiNAr (Ar = 2,6-iPr 2 C 6 H 3 ) 13 by Mindiola and Hillhouse, which engages in stoichiometric nitrene group transfer to isocyanides, 14 CO, 14 and ethylene 15 ( Figure 1). Formed via η 2 -azide adducts (dtbpe)Ni(η 2 -N 3 R), 16 the nickel(II) imides (dtbpe)NiNR (R = 1-adamantyl (Ad), 2,4,6-Me 3 C 6 H 2 (Mes)) 16 may be oxidized to their cationic nickel(III) analogues {(dtbpe)Ni NR} + , which exist in both S = 1/2 (R = Ad and Mes) and S = 3/2 states (R = Ad) ( Figure 1).…”

Iron‐ and Cobalt‐Catalyzed Synthesis of Carbene Phosphinidenes

“…[1][2][3][4][5] Complexes of the general type [L n M = PR] have been synthesized with many transition metals,and the ability of the phosphinidene ligand to display electrophilic or nucleophilic characteristics has enabled av ariety of phosphinidene-transfer reactions.W hile much of this chemistry was pioneered with 4d and 5d transition metals, [4,5] several important studies involving 3d metals have also been described. [6,7] Of particular significance is the three-coordinate nickel(II) phosphinidene complex [(dtbpe)Ni = P(C 6 H 3 -1,2-Mes 2 )] (dtbpe = di-tert-butylphosphinoethane,M es = mesityl), which is able to transfer the {PR} group to alkenes and alkynes in as toichiometric manner,t hus resulting in the formation of phosphorus heterocycles such as phosphiranes and phosphirenes. [6] Our interest in low-coordinate transition-metal chemistry has focused on iron and cobalt complexes of N-heterocyclic carbene (NHC) ligands.…”

“…[6,7] Of particular significance is the three-coordinate nickel(II) phosphinidene complex [(dtbpe)Ni = P(C 6 H 3 -1,2-Mes 2 )] (dtbpe = di-tert-butylphosphinoethane,M es = mesityl), which is able to transfer the {PR} group to alkenes and alkynes in as toichiometric manner,t hus resulting in the formation of phosphorus heterocycles such as phosphiranes and phosphirenes. [6] Our interest in low-coordinate transition-metal chemistry has focused on iron and cobalt complexes of N-heterocyclic carbene (NHC) ligands. [8][9][10][11][12] NHC-stabilized iron and cobalt complexes of terminal or bridging phosphinidene ligands are currently unknown, hence we are interested in developing the phosphinidene-transfer chemistry of complexes of the type [(NHC) n M(PR)] (M = Fe,C o).…”

“…The structures of 1 Fe and 1 Co (Figure 1; see Table S1 in the Supporting Information) are very similar to those of previously reported [(NHC)M(N'') 2 ]complexes. [8,9] 6 ]benzene at 343 K shows resonances resulting from the mesityl meta CH protons at d = 6.71 ppm, and the mesityl ortho-a nd para-methyl groups at 2.57 ppm and 2.07 ppm, respectively.T he nonequivalent IMe 4 N-methyl substituents occur at d = 4.77 and 3.30 ppm, and the non-equivalent IMe 4 backbone methyl groups occur at d = 1.83 and 1.31 ppm. Upon lowering the temperature,the resonances for the mesityl meta CH protons and the ortho-methyl groups broaden in as imilar manner to that of 2 Fe ,t hus suggesting similar fluxionality of the mesityl substituents and the IMe 4 ligands,however the poor solubility of 2 Co precluded further investigations at lower temperatures.…”