Masaaki YOSHIFUJI's Homepage

Research on Low Coordination Organophosphorus Compounds

Research Subjects

• Chemistry of organic reaction in heavier main group elements utilized by steric and/or electronic effect
• Synthesis, structure, reactivity, and physical properties of unusual organic compounds containing heavier main group elements
• Synthesis, structure, and physical properties of small-ring and/or highly strained organic compounds
• Synthesis, structure, physical properties, and reactivity of five- or seven-membered π-electronic systems
• Synthesis of new organic compounds provided with properties as organic conductors or magnets
• Hydrogen storage in phosphorus-containing exotic compounds

Overview of Research

Recently, modern organic chemistry has been covering broader areas than in the past, and in fact includes chemistry of almost all elements centering on the carbon atom. We have been interested in organic compounds carrying the heavier main group elements (or heteroatoms) such as sulfur, phosphorus, and selenium, stabilized by sterically bulky protecting groups. Thus, we have been involved in studies on synthesis, structure, reactivity, and physical properties of such unusual organic molecules. Since our target compounds are completely novel, most believed not to have existed as stable species unless kinetically or thermodynamically protected, we expect unusual properties or reactivities beyond our classical knowledge of organic chemistry, and those species are of interest in terms of both practical and theoretical science. New organic materials endowed with novel properties as conductors, magnets, liquid crystals, or hydrogen storage reservoirs can be expected to emerge from these studies on heteroatom chemistry as well as novel aromatic or π-electron systems.

Publications (Selected) [Full List]

• M. Yoshifuji, I. Shima, N. Inamoto, K. Hirotsu, and T. Higuchi, J. Am. Chem. Soc., 103, 4587-4589 (1981); Synthesis and Structure of Bis(2,4,6-tri-tert-butylphenyl)diphosphene; Isolation of a True "Phosphobenzene"
• M. Yoshifuji, K. Shibayama, N. Inamoto, T. Matsushita, and K. Nishimoto, J. Am. Chem. Soc., 105, 2495-2497 (1983); Isolation of Some Sterically Protected Unsymmetrical Diphosphenes; Nature of the Phosphorus-Phosphorus Double Bond
• M. Yoshifuji, K. Toyota, and N. Inamoto, J. Chem. Soc., Chem. Commun., 1984, 689-690; Isolation and Characterisation of the First Stable Diphospha-allene; P,P'-Bis(2,4,6-tri-t-butylphenyl)-1,3-diphospha-allene
• M. Yoshifuji, T. Hashida, N. Inamoto, K. Hirotsu, T. Hori­uchi, T. Higuchi, K. Ito, and S. Nagase, Angew. Chem., 97, 230-231 (1985); E/Z-Photoisomerisierung von metallkomplexierten Diphosphenen; Angew. Chem., Int. Ed. Engl., 24, 211-212 (1985); E/Z Photoisomerization of a Diphosphene of Carbonyl Metal Complexes (M = Cr, Mo, W)
• M. Yoshifuji, K. Toyota, T. Niitsu, N. Inamoto, Y. Okamoto, and R. Aburatani, J. Chem. Soc., Chem. Commun., 1986, 1550-1551; The First Separation of an Optically Active 1,3-Diphospha-allene of Axial Dissymmetry
• M. Yoshifuji, K. Toyota, M. Murayama, H. Yoshimura, A. Okamoto, K. Hirotsu, and S. Nagase, Chem. Lett., 1990, 2195-2198; Preparation of Sterically Protected 3,4-Bis(phosphinidene)cyclobutenes and their Isomerism
• K. Toyota, K. Tashiro, and M. Yoshifuji, Angew. Chem., 105, 1256-1258 (1993); Synthese und Struktur eines Diphospha[4]radialens; Angew. Chem., Int. Ed. Engl., 32, 1163-1165 (1993); Synthesis and Structure of Diphospha[4]radialene
• K. Toyota, K. Masaki, T. Abe, and M. Yoshifuji, Chem. Lett., 1995, 221-222; Preparation and Structure of Dichloropalladium(II) Complexes of Sterically Protected Diphosphinidenecyclobutene and Their Synthetic Application as Homogeneous Catalyst
• M. Yoshifuji, J. Chem. Soc., Dalton Trans., 1998, 3343-3349; Sterically protected organophosphorus compounds in low coordination states
• S. Sasaki, F. Murakami, and M. Yoshifuji, Angew. Chem., Int. Ed., 38, 340-343 (1999); Synthesis, structure, and radical anion of the first stable p-phosphaquinone. Angew. Chem., 111, 351-354 (1999); Synthese, Struktur und Radikalanion des ersten stabilen p-Phosphachinons
• S. Ito, H. Sugiyama, and M. Yoshifuji, Angew. Chem., Int. Ed., 39, 2781-2783 (2000); Isolation of a Kinetically Stabilized 1,3,6-Triphosphafulvene. Angew. Chem., 112, 2892-2894 (2000); Isolierung eines kinetisch stabilisierten 1,3,6-Triphosphafulvens
• F. Ozawa, H. Okamoto, S. Kawagishi, S. Yamamoto, T. Minami, and M. Yoshifuji, J. Am. Chem. Soc., 124, 10968-10969 (2002); (π-Allyl)palladium Complexes Bearing Diphosphinidenecyclobutene Ligands (DPCB): Highly Active Catalysts for Direct Conversion of Allylic Alcohols
• H. Sugiyama, S. Ito, and M. Yoshifuji, Angew. Chem., Int. Ed., 42, 3802-3804 (2003); Angew. Chem., 115, 3932-3934 (2003); Synthesis of a 1,3-Diphosphacyclobutane-2,4-diyl from Mes*C≡P (Mes* = 2,4,6-tBu₃C₆H₂)
• M. Yoshifuji, J. Synth. Org. Chem., 61, 1116-1123 (2003); Chemistry of Diphosphinidenecyclobutenes
• A. S. Gajare, K. Toyota, M. Yoshifuji, and F. Ozawa, Chem. Commun., 2004, 1994-1995; Application of a Diphosphinidenecyclobutene Ligand in Solvent Free Cu-catalysed Amination Reactions of Aryl Halides
• A. S. Gajare, R. S. Jensen, K. Toyota, M. Yoshifuji, and F. Ozawa, Synlett., 2005, 144-148; Low Coordinated Diphosphinidene Liganids: A New Entry for Stille Cross-Coupling of Aryl Bromides
• S. Kawasaki, A. Nakamura, K. Toyota, and M. Yoshifuji, Organometallics, 24, 2983-2987 (2005); Preparation and properties of 1,2-diferrocenyl substituted 3,4-diphosphinidenecyclobutenes and their complexes: the first application of a diphosphinidenecyclobutene unit as a linker of functional moieties
• F. Murakami, S. Sasaki, and M. Yoshifuji, J. Am. Chem. Soc., 127, 8926-8927 (2005); The First Phosphaquinomethanes and Their Anion Radicals
• S. Ito, M. Freytag, and M. Yoshifuji, J. Chem. Soc., Dalton, 2006, 710-713; Structural and coordination properties of 1,2-bis(cyclopropyl)-3,4-bis(tri-t-butylphenyl)-3,4-diphosphinidenecyclobutene prepared by dehydrogenative homocoupling of 3-cyclopropyl-1-phosphaallene
• M. Freytag, S. Ito, and M. Yoshifuji, Chem. Asian J., 1, 693-700 (2006); Coordination Behavior of Sterically Protected Phosphaalkenes on the AuCl Moiety Leading to Catalytic 1,6-Enyne Cycloisomerization
• S. Sasaki, K. Adachi, and M. Yoshifuji, Org. Lett., 9, 1729-1732 (2007); Synthesis of Dihydrothiophene, Thiophene, and Their Selenium Analogues Carrying Four Phosphoryl Groups
• S. Ito, H. Miyake, and M. Yoshifuji, Eur. J. Inorg. Chem., 2007, 3491-3496; 1,3-Dipolarophile Character of an Extremely Bulky Phosphaalkyne Mes*C≡P (Mes* = 2,4,6-t-Bu₃C₆H₂) Leading to the Formation of 1,2,4-Diazaphospholes of Unique H-Bonding Aspect
• S. Ito, J. Miura, N. Morita, M. Yoshifuji, and A. J. Arduengo, III, Inorg. Chem., 48, 8063-8065 (2009); Modeling the Direct Activation of Dihydrogen by a P₂C₂-Cyclic Biradical: Formation of a Cyclic Bis(P-H λ⁵-phosphorane)
• S. Ito, J. Miura, N. Morita, M. Yoshifuji, and A. J. Arduengo, III, Angew. Chem., Int. Ed., 47, 6418-6421 (2008); Angew. Chem., 120, 6518-6521 (2008); Poly(Biradicals): Oligomers of 1,3-Diphosphacyclobutane-2,4-diyl Units
• M. Yoshifuji, Science of Synthesis, Compounds with One Saturated Carbon-Heteroatom Bond: Organophosphorus Compounds (incl. RO-P and RN-P); Vol. 42, Ed. F. Mathey; Georg Thieme Verlag: Stuttgart; pp. 37-62 (2009); 42.2: Product Class 2: Oxo-, Thioxo-, Selenoxo-, and Iminophosphines and Diphosphenes
• S. Ito, J. Miura, N. Morita, M. Yoshifuji and A. J. Arduengo, III, Dalton Trans., 39, 8281-8287 (2010); Diverse reactions of sterically protected 1,3-diphosphacyclobutane-2,4-diyls with hydride

Recent External Seminars

• Texas Tech University, Lubbock (January 17, 2006, Prof. Satomi Niwayama): Unusual Phosphorus Compounds with Extremely Bulky Substituents
• The University of Texas at Austin (April 19, 2006, Prof. Alan H. Cowley): Chemistry of Sterically Protected Unusual Phosphorus Compounds
• University of Wisconsin, Madison (September 22, 2006, Prof. Robert West): Chemistry of Sterically Protected Unusual Phosphorus Compounds
• Washington University in St. Louis, Missouri (March 29, 2007, Prof. Peter Gaspar): Chemistry of Sterically Protected Unusual Phosphorus Compounds
• Ningbo University, Zhejiang, China (April 20, 2007, Prof. Hongze Liang): New Chemistry of Phosphorus Compounds with Unusual Structures
• Universität Jena, Germany (June 18, 2007, Prof. Dr. Wolfgang Weigand): Chemistry of Sterically Protected Simple but Unusual Organophosphorus Compounds
• Universität Erlangen-Nürnberg, Germany (June19, 2007Prof. Dr. Ulrich Zenneck): Unusual Phosphorus Compounds Stabilized with Sterically Bulky Substituents
• Universität Regensburg, Germany (June 20, 2007, Prof. Dr. Manfred Scheer): Chemistry on Simple but Unusual Phosphorus Compounds
• Universität Bonn, Germany (July, 2, 2007, Prof. Dr. Rainer Streubel and Prof. Dr. Edgar Niecke): Chemistry of Sterically Protected Simple but Unusual Organophosphorus Compounds
• Vrije Universiteit Amsterdam (July 27, 2007, Prof. Dr. Koop Lammertsma): New Chemistry on Unusual Organophosphorus Compounds
• Universität Stuttgart, Germany (July 31, 2007, Prof. Dr. Dietrich Gudat): New Chemistry of Sterically Protected Simple but Unusual Organophosphorus Compounds
• Technische Universität Braunschweig, Germany (August 6, 2007, Prof. Dr. Wolf-Walther du Mont and Prof. Dr. Reinhard Schmutzler): Sterically Protected Simple but Unusual Organophosphorus Compounds
• N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow (June 3, 2008, Prof. Irina L. Odinets and Prof. Yuri G. Gololobov): New Chemistry of Unusual Organophosphorus Compounds
• University of Mississippi, Oxford (April 8, 2009, Prof. Keith Hollis): New Chemistry of Unusual Organophosphorus Compounds
• Institut de Ciència de Materials de Barcelona, Bellaterra, Barcelona (July 10, 2009, Prof. Francesc Teixidor and Prof. Clara Viñas): New Chemistry of Unusual Organophosphorus Compounds
• Universität Bonn, Germany (July 5, 2010, Prof. Dr. Rainer Streubel): Sterically and electronically stabilized singlet biradical species of P2C2 heterocyclic rings
• Technische Universität Braunschweig, Germany (July 7, 2010, Prof. Dr. Wolf-Walther du Mont and Dr. Jeroen S. Dickschat): Supermesityl steric effect on carbon and phosphorus atoms
• Universität Chemnitz, Germany (July 8, 2010, Prof. Dr. Heinrich Lang): Sterically Protected simple but unusual organophosphorus compounds
• Technische Universität Braunschweig, Germany (October 14, 2011, Prof. Dr. Wolf-Walther du Mont): Low Coordinate Phosphorus Compounds for 30 Years
• Universität Bonn, Germany (October 24, 2011, Prof. Dr. Rainer Streubel): Low Coordinate Phosphorus Compounds for 30 Years

Recent Oral Presentations at Conferences and Meetings

• The 14th International Conference on Chemistry of Phosphorus Compounds (Kazan, Russia, June 25-30, 2005): M. Yoshifuji, Recent Developments in the Chemistry of Low-coordinated Organophosphorus Compounds (Arbuzov Prize Laureate Lecture)
• The 231st ACS National Meeting (Atlanta, GA, March 26-30, 2006): R. S. Jensen, A. S. Gajare, K. Toyota, M.Yoshifuji and F. Ozawa, Novel Bidentate Ligands Containing Low-coordinated Phosphorus for Catalytic Reactions
• The 2nd Core-to-Core Symposium on Main Group Element Chemistry (Tokyo, Japan, Aug. 26-28, 2006): M. Yoshifuji and S. Ito, Chemistry of Stable 1,3-Diphosphacyclobutane-2,4-diyls
• The 15th International Conference on Chemistry of Phosphorus Compounds (St. Petersburg, Russia, May 25-30, 2008): M. Yoshifuji, A. J. Arduengo, and S. Ito, Preparation, structure, and Reactivity of Stable 1,3-Diphosphacyclobutane-2,4-diyls
• The 9th International Conference on Heteroatom Chemistry (Oviedo, Spain, June 30-July 4, 2009): S. Ito, J. Miura, N. Morita, M. Yoshifuji, and A. J. Arduengo, Catenation of P-Hetorocyclic Biradical Chromophores Featuring Non-Conjugative Communication
• The 18th International Conference on Phosphorus Chemistry (Wroclaw, Poland, July 11-15, 2010): S. Ito, J. Miura, N. Morita, M. Yoshifuji, and A. J. Arduengo, Modeling the direct activation of dihydrogen by a P₂C₂-cyclic biradical: formation of a cyclic bis(P-H λ⁵-phosphorane)
• The 19th International Conference on Phosphorus Chemistry (Rotterdam, The Netherlands, July 8-12, 2012): M. Yoshifuji and S. Ito, Phosphorus Version of the Fritsch-Buttenberg-Wiechell Reaction
• The 7th Seminar on Organo-Element Chemistry (Uji-Kyoto, Japan, November 29-30): M. Yoshifuji, Chemistry of Sterically Protected Phosphorus Compounds---Unusual Phosphorus Compounds---
• The 20th International Conference on Phosphorus Chemistry (Dublin, Ireland, June 28-July 2, 2014): M. Yoshifuji and S. Ito, Studies on Intramolecular Cyclization of 2,4,6-tri-tert-butylphenyl-P=C:
• The 21st International Conference on Phosphorus Chemistry (Kazan, Russia, June 5-10, 2016): M. Yoshifuji, Sterically protected organophosphorus compounds of unusual structures
• The 22nd International Conference on Phosphorus Chemistry (Budapest, Hungary, July 8-13, 2018): M. Yoshifuji, Stereochemical Features of Low-coordinate Organophosphorus Compounds
• The 23rd International Conference on Phosphorus Chemistry (Częstochowa, Poland, July 4-9, 2021): M. Yoshifuji, Low Coordinate Phosphorus Compounds for 40 Years