Katsuki, Tsutomu

Metal complexes as catalysts for oxygen, nitrogen and carbon-atom transfer reactions (Tsutomu Katsuki) Metal complexes as catalysts for H-X (X = B,CN, Si, N, P) addition to CC multiple bonds (M. Whittlesey) Metal complexes as catalysts for C-C cross-coupling reactions (I. Beletskaya, A.V. Cheprakov)... 

Tsutomu Katsuki, Department of Chemistry, Faculty of Science, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukouka 812-81, JAPAN... 

In the same year (1990) that Jacobsen reported his asymmetric epoxidation, a group led by Tsutomu Katsuki at the University of Kyushu in Japan reported a closely related asymmetric epoxidation. The chiral catalyst is also a salen and the metal manganese. The oxidant is iodosobenzene (Phl=0) but this method works best for E-alkenes. It is no coincidence that Katsuki and Jacobsen both worked for Sharpless. It is not unusual for similar discoveries to be made independently in different parts of the world, the Katsuki manganese salen complex... 

K. Barry Sharpless and Tsutomu Katsuki Titanium-catalyzed asymmetric epoxidation... 

Prof. Tsutomu Katsuki Faculty of Science Kyushu University Hakozaki, Higashi-ku Fukuoka 812-8581 Japan... 

Asymmetric Epoxidation of Allylic Alcohols The Katsuki-Sharpless Epoxidation Reaction Tsutomu Katsuki and Victor S. Martin... 

The first of Sharpless s reactions is an oxidation of alkenes by asymmetric epoxidation. You met vanadium as a transition-metal catalyst for epoxidation with t-butyl hydroperoxide in Chapter 32, and this new reaction makes use of titanium, as titanium tetraisopropoxide, Ti(0/-Pr)4, to do the same thing. Sharpless and his co-worker Tsutomu Katsuki surmised that by adding a chiral ligand to the titanium catalyst they might be able to make the reaction asymmetric. The ligand that works best is diethyl tartrate, and one example of the reaction is shown below. 

Mn(III) sits neatly in a tetracoordinate pocket in the ligand, and catalyses the epoxidation of simple alkenes by sodium hypochlorite, NaOCl, ordinary domestic bleach. Best results are obtained when the alkenes are cis (although an alternative range of ligands, developed by Tsutomu Katsuki, work well with trans alkenes), and one of the most significant applications of the Jacobsen epoxidation is with indene, which gives an epoxide in 84% ee with <1% of the catalyst. The mechanism of the reaction is complex and not fully understood, although it probably involves a Mn(V) oxo species and may involve radical intermediates. 

Although the enantioselective oxidation of alkyl aryl sulfides is well developed, much less is known about dialkyl sulfides. Tsutomu Katsuki of Kyushu University has designed J. Am. Chem. Soc. 2007, 129, 8940) an Fe(salan) complex that combines with aqueous to oxidize alkyl methyl sulfides in high ee. 

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