• Open Access

A Highly Active Bifunctional Iridium Complex with an Alcohol/Alkoxide-Tethered N-Heterocyclic Carbene for Alkylation of Amines with Alcohols

Authors

  • Agnieszka Bartoszewicz,

    1. Department of Organic Chemistry, Stockholm University, 10691 Stockholm (Sweden), Fax: (+46) 8-154908
    2. Berzelii Centre EXSELENT on Porous Materials, Stockholm University, 10691 Stockholm (Sweden)
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  • Dr. Rocío Marcos,

    1. Department of Organic Chemistry, Stockholm University, 10691 Stockholm (Sweden), Fax: (+46) 8-154908
    2. Berzelii Centre EXSELENT on Porous Materials, Stockholm University, 10691 Stockholm (Sweden)
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  • Dr. Suman Sahoo,

    1. Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm (Sweden)
    2. Berzelii Centre EXSELENT on Porous Materials, Stockholm University, 10691 Stockholm (Sweden)
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  • Dr. A. Ken Inge,

    1. Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm (Sweden)
    2. Berzelii Centre EXSELENT on Porous Materials, Stockholm University, 10691 Stockholm (Sweden)
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  • Prof. Xiaodong Zou,

    1. Department of Materials and Environmental Chemistry, Stockholm University, 10691 Stockholm (Sweden)
    2. Berzelii Centre EXSELENT on Porous Materials, Stockholm University, 10691 Stockholm (Sweden)
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  • Dr. Belén Martín-Matute

    Corresponding author
    1. Department of Organic Chemistry, Stockholm University, 10691 Stockholm (Sweden), Fax: (+46) 8-154908
    2. Berzelii Centre EXSELENT on Porous Materials, Stockholm University, 10691 Stockholm (Sweden)
    • Department of Organic Chemistry, Stockholm University, 10691 Stockholm (Sweden), Fax: (+46) 8-154908===

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Abstract

A series of new iridium(III) complexes containing bidentate N-heterocyclic carbenes (NHC) functionalized with an alcohol or ether group (NHC[BOND]OR, R=H, Me) were prepared. The complexes catalyzed the alkylation of anilines with alcohols as latent electrophiles. In particular, biscationic IrIII complexes of the type [Cp*(NHC-OH)Ir(MeCN)]2+2[BF4] afforded higher-order amine products with very high efficiency; up to >99 % yield using a 1:1 ratio of reactants and 1–2.5 mol % of Ir, in short reaction times (2–16 h) and under base-free conditions. Quantitative yields were also obtained at 50 °C, although longer reaction times (48–60 h) were needed. A large variety of aromatic amines have been alkylated with primary and secondary alcohols. The reactivity of structurally related iridium(III) complexes was also compared to obtain insights into the mechanism and into the structure of possible catalytic intermediates. The IrIII complexes were stable towards oxygen and moisture, and were characterized by NMR, HRMS, single-crystal X-ray diffraction, and elemental analyses.

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