Assistant Professor · The University of Tokyo

Taichi Koike

Organic Functional Design Group · Dept. of Chemistry & Biotechnology

Graduate School of Engineering, The University of Tokyo
Toyota Riken Scholar  ·  JST ACT-X Researcher  ·  RIKEN Visiting Researcher

Low-coordinate main group Carbon atom transfer Silicon chemistry Carbene / Silylene Unusual bonding
Publications Contact / Links
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Research

Molecules at the frontier
of bonding and reactivity

★ Corresponding Author · ACIE 2026
Azetidinylideneketenimines as a Multimodal Synthetic Platform
Angew. Chem. Int. Ed. 2026, accepted

Coordination chemistry and cycloaddition-triggered transformations of isolable azetidinylideneketenimines — a versatile reactive platform built on strained four-membered rings.

DOI →
★ Corresponding Author · JACS 2023
Cyclobutenylidene: A Multifaceted Two-Coordinate Carbon Species
J. Am. Chem. Soc. 2023, 145, 9264–9272

The first isolable cyclobutenylidene, obtained via skeletal editing of a cyclopropenylidene — a carbene with rich reactivity arising from its strained bicyclic carbon framework.

DOI →
Science 2024
Ph₃PCN₂: A stable reagent for carbon-atom transfer
Science 2024, 385, 305–311

Stable phosphorus ylide Ph₃PCN₂ enables stoichiometric and catalytic single-atom carbon transfer — a previously elusive transformation now unlocked as a practical synthetic tool.

Open in Science
01
Low-valent Main Group Element Chemistry

Synthesis and characterization of low-coordinate silicon and carbon species with unusual electronic structures — silylones, silylenes, carbenes, and beyond. Stabilized by sterically demanding ligands, these molecules challenge conventional bonding theories.

SilyleneCarbeneSilyloneLow-coordinate Si
02
Carbon & Main Group Atom Transfer Chemistry

Design of isolable, bench-stable reagents for single-atom transfer reactions. The carbon-atom transfer reagent Ph₃PCN₂ (Science 2024) opens new retrosynthetic disconnections impossible with classical methods.

Atom transferYlide chemistryDiazo compounds
03
Exotic π-Electron Systems & Unusual Bonding

Exploration of silicon-based π systems with non-classical bonding — 3-electron-2-center bonds, hypervalent/hypoelectronic species, and strained ring systems. Experiment guided by quantum chemical computation.

Si=B bondRadical anionπ systemsDFT

Publications

Selected papers

2026
Azetidinylideneketenimines as a Multimodal Synthetic Platform: Coordination Chemistry and Cycloaddition-Triggered Transformations
T. Koike*, K. Ito, S. Ishida, T. Iwamoto*
Angew. Chem. Int. Ed. 2026, accepted
DOI →
2025
Cyclic (Alkyl)(amino)silylene Aluminum(III) Iodide Complex and Its Nucleophile Dependent Reactivities
T. Koike, A. Sato, N. Sakurata, T. Iwamoto*
Organometallics 2025, 44, 1013–1017
DOI →
2025
Ph₃PC – A Monosubstituted C(0) Atom in Its Triplet State
Y. Kutin, T. Koike, M. Drosou, A. Schnegg, D. Pantazis*, M. Kasanmascheff*, M. M. Hansmann*
Angew. Chem. Int. Ed. 2025, 64, e202424166
DOI →
2024
Ph₃PCN₂: A stable reagent for carbon-atom transfer
T. Koike, J.-K. Yu, M. M. Hansmann*
Science 2024, 385, 305–311
DOI →
2024
Isolable Si=B Analogue of a Vinyl Halide: A Building Block for Facile Access toward Silicon–Boron Multiple Bonded Species
T. Koike, N. Sakurata, S. Ishida, T. Iwamoto*
Angew. Chem. Int. Ed. 2024, 63, e202411283
DOI →
2024
Cycloadditions of Diazoalkenes with P₄ and tBuCP: Access to Diazaphospholes
S. Hauer, J. Reitz, T. Koike, M. M. Hansmann*, R. Wolf*
Angew. Chem. Int. Ed. 2024, e202410107
DOI →
2023
Cyclobutenylidene: A Multifaceted Two-Coordinate Carbon Species Obtained via Skeletal Editing of a Cyclopropenylidene
T. Koike*, T. Iwamoto*
J. Am. Chem. Soc. 2023, 145, 9264–9272
DOI →
2022
Synthesis, Structure and Electronic Properties of a Stable π-Type 3-Electron-2-Center-Bonded Species: A Silicon Analogue of a Bicyclo[1.1.0]butane Radical Anion
T. Koike, R. Osawa, S. Ishida, T. Iwamoto*
Angew. Chem. Int. Ed. 2022, 61, e202117584
DOI →
2022
Twisted Push–Pull Disilenes Obtained by Direct 1,2-Hydro/Chloroborylation of a Silylone
T. Koike, T. Iwamoto*
Chem. Commun. 2022, 58, 8061–8064
DOI →
2021
Conformationally Switchable Silylone: Electron Redistribution Accompanied by Ligand Reorientation around a Monatomic Silicon
T. Koike, T. Nukazawa, T. Iwamoto*
J. Am. Chem. Soc. 2021, 143, 14332–14341
DOI →
2021
Intermolecular C–H Activation at the Allylic/Benzylic and Homoallylic/Homobenzylic Positions of Cyclic Hydrocarbons by a Stable Divalent Silicon Species
T. Koike, T. Kosai, T. Iwamoto*
Chem. Eur. J. 2021, 27, 724–734
DOI →
2019
1,4-Dehydrogenation with a Two-Coordinate Cyclic (Alkyl)(amino)silylene
T. Koike, T. Kosai, T. Iwamoto*
Chem. Eur. J. 2019, 25, 9295–9302
DOI →
Full list on researchmap →

About & CV

Career & biography

Taichi Koike

I am an Assistant Professor in the Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo (Masai Group). My research explores the chemistry of low-coordinate and low-valent main group elements — molecules that push the boundaries of classical bonding theory.

I synthesize and characterize highly reactive, often unprecedented species such as free carbenes, silylones, and exotic π-bonded systems. A key focus is developing stable reagents for atom-transfer reactions — inspired by the discovery of Ph₃PCN₂ as a practical carbon-atom transfer agent (Science 2024).

I also hold concurrent appointments as a Toyota Riken Scholar and a Visiting Researcher at RIKEN, and pursue JST ACT-X research on click-type reactions of low-coordinate elements as a route to functional π-electron materials.

Download CV (PDF) ↓
Positions
Assistant ProfessorThe University of Tokyo
2025–
Toyota Riken ScholarToyota Physical & Chemical Research Institute
2025–
JST ACT-X Researcher
2025–
Visiting ResearcherRIKEN
2025–
Postdoctoral Fellow (Humboldt)TU Dortmund (Prof. M. M. Hansmann)
2023–25
JSPS Research Fellow DC1Tohoku University (Prof. T. Iwamoto)
2020–23
Education
Ph.D. ChemistryTohoku University
2023
M.Sc. ChemistryTohoku University
2020
B.Sc. ChemistryTohoku University
2018
Selected Awards
★JSPS Ikushi Prize（育志賞）
2023
★Inoue Research Award（井上研究奨励賞）
2024
Tohoku Univ. President's Award
2023
Aoba Foundation Prize
2023
Chemistry Letters Young Researcher Award
2022
Ohtsu Conference Award Fellow
2022
+ 9 further presentation / poster awards
Research Funding
2026–28
Toyota Riken Scholar
B,N-π functionalization reagents for unexplored π-electron materials
2025–28
JST ACT-X
Click-type reactions of low-coordinate main group elements for functional chemistry (JPMJAX25D6)
2025–27
JSPS Grant-in-Aid（スタート支援）
Low-coordinate main group element photoredox chemistry (25K23580)
2023–25
Alexander von Humboldt Fellowship
Carbon-atom transfer chemistry, TU Dortmund

Contact

Get in touch

Open to collaborations, seminar invitations, and prospective students & postdocs.

tkoike@chembio.t.u-tokyo.ac.jp researchmap ORCID @SiAdamas J-GLOBAL

Dept. of Chemistry & Biotechnology, Graduate School of Engineering
The University of Tokyo, Bunkyo-ku, Tokyo, Japan