Intermolecular IrCl

Allyl carbonate 81 reacts with primary and secondary amines 82 to afford branched aUylic amination products 83 under the influence of a [IrCl(cod)]2/ P(OPh)3 catalyst (Equation 10.17) [38]. In this reaction, alcohols such as ethanol and methanol proved to be the best solvents, while both intermolecular and intramolecular enantioselective aUylic aminations were reported by using chiral phosphoramidites as ligands [39]. The aUylic amination of (Zj-2-noneyl carbonate 85 with 82 in the presence of [IrCl(cod)]2 and P(OPh)3 afforded Z-linear aUylic amines (Equation 10.18) [38]. In this reaction, the Z-geometry of 85 was completely retained. 

Following the success with cobalt and rhodium, Shibata reported Ir(i)-based enantioselective catalytic reaction. Right after their observation that the efficiency of [IrCl(COD)]2-catalyzed PKR substantially increased by addition of a phosphane co-ligand, they moved directly to use chiral phosphanes and examined the enantioselectivity. " TON and TOE of the reaction were low and the number of examples was limited. Typically, the reaction required a fair amount of Ir(i) catalyst [IrCl(COD)]2 (0.1-0.15 equiv.) and (reaction time. However, this has remained as the best in terms of enantioselectivity to date. Moreover, this catalytic system provided the first asymmetric intermolecular reaction as well. 

Intermolecular oxidative addition of H—C usually involves activated H—C bonds. The weak acid HCN reacts with transition-metal complexes e.g., HCN and NiL lead to the hydride complexes HNi(CN)Lj (L = various phosphorus ligands). The versatile complex IrCl(CO)(PPh3)j adds HCN cleanly in CH Clj at RT to form HIr(CN)(Cl(PPhj)2. The zero-valent complexes Pt(PPhj) or Pt(PPh3)3 also add HCN to yield HPt(CN)(PPh3)j. Reactions of HMNp(dmpe)j (M = Fe, Ru, Os Np = 2-naphthyl dmpe = Me PCH CH PMej) with HCN and terminal acetylenes give HMR(dmpe)2 that contain new M—C bonds (R = — CN, — CjR ) . 

As part of comparative studies, Iyer [47] reported the use of Vaska s complex [IrCl(CO)(PPh3)2l (92) in intermolecular Mizoroki-Heck-type reactions of methyl acrylate (1) and styrene (2). Aryl iodides could be used as electrophiles, while bromobenzene, chlorobenzene and aliphatic halides gave no desired product. The catalytic activity was found to be lower than that observed when using Wilkinson s complex [RhCl(PPh3)3] (84). Thus, a higher reaction temperature of 150 °C was mostly required. In contrast to the corresponding cobalt-catalysed reaction, however, Vaska s complex (92) proved applicable to orf/io-substituted aryl iodides (Scheme 10.33). 

An intermolecular hydroamination using pre-catalyst IrCl(PEt3)2(C2H4)2 (32) has been elucidated as an overall c s-addition of the N-H bond across norbomene (33) (Scheme 9) [55]. The intermediate was crystaUographicaUy characterized as complex P, which was derived from migratory insertion of 33 into Ir-N bond of O, and both of its newly formed Ir-C and C-N bonds occupied the exo-face of 33. 

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