8.4.5. Nitromercuration Reactions 3878 9. Hydroamination of Alkenes and Alkynes under Microwave Irradiation 3878 * To whom correspondence should be addressed. Phone: +49 241 8

Hydroamination: direct addition of amines to alkenes and alkynes.

The catalytic production of organic molecules is one of the most important applications of organometallic chemistry. For this purpose the distinct reaction chemistry of organic ligands covalently bound to transition metals is exploited. Most organometallic chemistry has focused on the formation of carboncarbon or carbon-hydrogen bonds. The platinum group metals, in particular Pd and Rh, have been the most commonly used elements insfrequently commercializedscatalytic processes that include hydrogenation, hydroformylation and others. On the other hand, carbon-oxygen and carbon-nitrogen bonds are found in the majority of organic molecules and are of particular importance in physiologically active substances. However, catalytic organometallic reactions that lead to the formation of carbonheteroatom bonds are less common.1,2 The catalytic construction of carbon-nitrogen bonds in amines is particularly rare.3-10 Clearly, efficient catalytic routes to nitrogen based molecules are of great interest.11 Especially useful are catalytic hydroaminations of olefins and alkynes which avoid production of byproducts, like salts, generally observed in metal-catalyzed aminations of C-X derivatives (X ) e.g., halogen). However, known aminations of olefins often require stoichiometric use of transition metals and general methods for carrying out aminations catalytically are not yet available.12,13 Most of the present enantioselective syntheses of molecules bearing an amine functionality use classical stoichiometric reactions with chiral auxiliaries or utilize enantiomerically pure starting material.14-16 Hydroamination of alkenes and alkynes, which constitutes the formal addition of a N-H bond across a carbon-carbon multiple bond (Scheme 1), is a transformation of seemingly fundamental simplicity and would appear to offer the most attractive route to numerous classes of organo-nitrogen molecules such as alkylated amines, enamines or imines. Organic chemists have developed various synthetic approaches for the amination of olefins.17-19 Direct addition of nucleophiles H-NR2 to activated alkenes is of general importance for the synthesis of compounds with nitrogen atoms â to groups such as keto, ester, nitrile, sulfoxide, or nitro.13,20-23 These additions usually lead to the anti-Markovnikov products. On the other hand aliphatic olefins as well as most aromatic olefins are often aminated to give the Markovnikov product. One possibility to reverse the reactivity of aliphatic olefins is the use of electrophilic nitrogen radicals which have been used to obtain anti-Markovnikov products.24 In the past much work has been done on the activation of alkenes with stoichiometric amounts of metal.24 Reactions are mostly promoted by complexes of titanium,25 iron,26 zirconium,27 palladium28-31 and mercury.32,33 However, catalytic additions of amines H-NR2 to nonactivated double or triple bonds are still rare. Two basic approaches have been employed to catalytically effect aminations and involve either alkene/alkyne or amine activation routes (Scheme 2).34,140 Alkene activation is generally accomplished with late-transition-metal catalysts, which render coordinated olefins more susceptible to attack by † Dedicated to Dipl. Chem. Martin Eichberger (deceased 11/20/ 1997). 675 Chem. Rev. 1998, 98, 675−703

Metal-Initiated Amination of Alkenes and Alkynes.

Late transition metal-catalyzed hydroamination and hydroamidation.

Palladium-Catalyzed Intermolecular Hydroamination of Vinylarenes Using Arylamines

Reaction of benzyl-2,2-diphenyl-4-pentenylamine with a catalytic 1:2 mixture of [PtCl2(H2CCH2)]2 (2.5 mol %) and PPh3 in dioxane at 120 °C for 16 h led to isolation of 1-benzyl-2-methyl-4,4-diphenylpyrrolidine in 75% yield. A number of γ- and δ-amino olefins underwent intramolecular hydroamination to form the corresponding pyrrolidine derivatives in moderate to good yield. The reaction displayed excellent functional group compatibility and low moisture sensitivity.

Platinum-catalyzed intramolecular hydroamination of unactivated olefins with secondary alkylamines.

Addition reactions on coordinated olefinic ligands. II. Reaction between amines and monoolefins coordinated in cis-dichloro(olefin) (tert-phosphine)platinum(II) complexes

Addition reactions on coordinated olefinic ligands. I. Reactions of amines with diene complexes of platinum(II) and palladium(II)

Determination des structures cristallines des 2 complexes [PtCl 2 (C 2 H 4 )(Me 2 CHN=CHCH=NNMe 2 )] et [PtCl 2 (E−CH 3 CH=CHCH 3 )(Me 3 CN=CHCH=NCMe 3 )]. Correlation entre la geometrie des complexes et les proprietes electroniques et steriques des coordinats azotes et des coordinats olefines. Spectes RMN en solution

Five- vs. four-coordination in platinum(II)-olefin complexes with bidentate nitrogen ligands

The chiroptical properties of five-co-ordinated complexes of general formula [PtCl2(N–N)(olefin)], with olefin ligands having either electron-donating or electron-withdrawing substituents, have been investigated. A comparison is also made with related square-planar complexes. The optical properties and the c.d. spectra of several enantiomers are reported. A correlation rule between the sign of the c.d. bands in the regions around 29 000 and 44 000 cm–1 and the absolute configuration is found for complexes containing prochiral ethylene homologues. For both bands a positive sign seems to be diagnostic for the R configuration.

Augusto De Renzi

Papers

Addition reactions on coordinated olefinic ligands. II. Reaction between amines and monoolefins coordinated in cis-dichloro(olefin) (tert-phosphine)platinum(II) complexes

Addition reactions on coordinated olefinic ligands. I. Reactions of amines with diene complexes of platinum(II) and palladium(II)

Five- vs. four-coordination in platinum(II)-olefin complexes with bidentate nitrogen ligands

Chiroptical properties of five-co-ordinated olefin complexes of platinum (II)