Vol.:(0123456789)
Topics in Current Chemistry (2019) 377:31
https://doi.org/10.1007/s41061-019-0256-1
1 3
REVIEW
Cationic Organic Catalysts or Ligands in Concert with Metal
Catalysts
Kohsuke Ohmatsu
1
· Takashi Ooi
1
Received: 16 August 2019 / Accepted: 9 October 2019 / Published online: 25 October 2019
© Springer Nature Switzerland AG 2019
Abstract
Cooperative dual catalysis and bifunctional catalysis have emerged as reliable strategies for the development of hitherto difficult asymmetric transformations because
they could deliver new reactivity and selectivity, and allow for the employment of
substrates not amenable to reaction systems relying on a single, monofunctional catalysts. Furthermore, these modes of catalysis often improve yields and stereoselectivities via the precise recognition and simultaneous activation of nucleophiles and
electrophiles. Efforts towards utilizing chiral cationic organic catalysts for asymmetric cooperative catalysis with metal complexes have provided a unique platform to
address the challenging issues associated with reaction development. Chiral onium
ions, such as tetraalkylammonium, guanidinium, and azolium ions, are employed
mainly to control the reactivity and stereochemistry of anionic intermediates through
electrostatic and hydrogen-bonding interactions. Metal complexes complement the
synergy of the catalysis by activating the substrates via the formation of electrophilic π-allyl complexes, Lewis acid–base adducts, nucleophilic ate complexes, etc.
The electrostatic interactions between cations and anions also offer a means to construct complex molecular assemblies, and, thus, onium ions are useful not only for
controlling pairing with anionic species, but also for the design of supramolecular
catalysts. The combination of onium ions and metal complexes leads to the introduction of novel concepts and powerful strategies for the development of catalysts
and chemical transformations.
Keywords Onium ion · Hybrid catalysis · Asymmetric carbon–carbon bond
formation · Ion-paired ligand
* Takashi Ooi
tooi@chembio.nagoya-u.ac.jp
1
Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering,
Institute of Transformative Bio-Molecules (ITbM), Nagoya University, Nagoya 464-8601, Japan
Reprinted from the journal
131
Chapter 6 was originally published as Ohmatsu, K. & Ooi, T. Topics in Current Chemistry (2019) 377: 31.
https://doi.org/10.1007/s41061-019-0256-1.
Topics in Current Chemistry (2019) 377:31
https://doi.org/10.1007/s41061-019-0256-1
1 3
REVIEW
Cationic Organic Catalysts or Ligands in Concert with Metal
Catalysts
Kohsuke Ohmatsu
1
· Takashi Ooi
1
Received: 16 August 2019 / Accepted: 9 October 2019 / Published online: 25 October 2019
© Springer Nature Switzerland AG 2019
Abstract
Cooperative dual catalysis and bifunctional catalysis have emerged as reliable strategies for the development of hitherto difficult asymmetric transformations because
they could deliver new reactivity and selectivity, and allow for the employment of
substrates not amenable to reaction systems relying on a single, monofunctional catalysts. Furthermore, these modes of catalysis often improve yields and stereoselectivities via the precise recognition and simultaneous activation of nucleophiles and
electrophiles. Efforts towards utilizing chiral cationic organic catalysts for asymmetric cooperative catalysis with metal complexes have provided a unique platform to
address the challenging issues associated with reaction development. Chiral onium
ions, such as tetraalkylammonium, guanidinium, and azolium ions, are employed
mainly to control the reactivity and stereochemistry of anionic intermediates through
electrostatic and hydrogen-bonding interactions. Metal complexes complement the
synergy of the catalysis by activating the substrates via the formation of electrophilic π-allyl complexes, Lewis acid–base adducts, nucleophilic ate complexes, etc.
The electrostatic interactions between cations and anions also offer a means to construct complex molecular assemblies, and, thus, onium ions are useful not only for
controlling pairing with anionic species, but also for the design of supramolecular
catalysts. The combination of onium ions and metal complexes leads to the introduction of novel concepts and powerful strategies for the development of catalysts
and chemical transformations.
Keywords Onium ion · Hybrid catalysis · Asymmetric carbon–carbon bond
formation · Ion-paired ligand
* Takashi Ooi
tooi@chembio.nagoya-u.ac.jp
1
Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering,
Institute of Transformative Bio-Molecules (ITbM), Nagoya University, Nagoya 464-8601, Japan
Reprinted from the journal
131
Chapter 6 was originally published as Ohmatsu, K. & Ooi, T. Topics in Current Chemistry (2019) 377: 31.
https://doi.org/10.1007/s41061-019-0256-1.