Junji Furukawa

Bio: Junji Furukawa is an academic researcher from Kyoto University. The author has contributed to research in topics: Polymerization & Copolymer. The author has an hindex of 30, co-authored 413 publications receiving 4347 citations. Previous affiliations of Junji Furukawa include University of Tokyo & Sumitomo Chemical.

Infrared studies of stereoregular polymerization of methyl methacrylate and methacrylonitrile by organometallic compounds

Abstract: Infrared spectra of reaction mixtures of methyl methacrylate or methacrylonitrile with an equimolar amount of organometallic compounds were investigated in relation to the stereoregulating ability of the catalysts in polymerization. It was found that the carbonyl or nitrile stretching frequency correlated with the stereoregularity of polymers prepared with the corresponding catalysts; i.e., the higher the frequency, the higher the isotacticity. From these results a mechanism of isotactic polymer formation was proposed, in which catalyst counterion was located near the carbonyl group in polymer terminal and that of monomer to be reacted, and consequently the isotactic polymerization is facilitated.

The atom economy--a search for synthetic efficiency

Abstract: Efficient synthetic methods required to assemble complex molecular arrays include reactions that are both selective (chemo-, regio-, diastereo-, and enantio-) and economical in atom count (maximum number of atoms of reactants appearing in the products). Methods that involve simply combining two or more building blocks with any other reactant needed only catalytically constitute the highest degree of atom economy. Transition metal-catalyzed methods that are both selective and economical for formation of cyclic structures, of great interest for biological purposes, represent an important starting point for this long-term goal. The limited availability of raw materials, combined with environmental concerns, require the highlighting of these goals.

Hydroamination: direct addition of amines to alkenes and alkynes.

Abstract: 8.4.5. Nitromercuration Reactions 3878 9. Hydroamination of Alkenes and Alkynes under Microwave Irradiation 3878 * To whom correspondence should be addressed. Phone: +49 241 8

Volume phase transition in a nonionic gel

Abstract: Nonionic N‐isopropylacrylamide gel was found to undergo a discontinuous phase transition by changing a solvent composition or temperature. The observation that polymer gel with and without charge can undergo a first order volume phase transition is an evidence for the universality of the phase transition of polymer gels.

Transition Metal-Mediated Cycloaddition Reactions

Abstract: 5.7. [32π + 32σ] Cycloadditions 74 5.8. [44π + 22π] Cycloadditions 75 6. Seven-Membered Ring Formation 78 6.1. [44π + 32σ] Cycloadditions 78 6.2. [52π+2σ + 22π] Cycloadditions 79 7. Eight-Membered Ring Formation 79 7.1. [22π + 22π + 22π + 22π] Cycloadditions 80 7.2. [44π + 22π + 22π] Cycloadditions 80 7.3. [44π + 44π] Cycloadditions 81 7.4. [66π + 22π] Cycloadditions 83 8. Ten-Membered Ring Formation 85 9. Conclusion and Remarks 87

Stereoselective Cyclopropanation Reactions

Abstract: Organic chemists have always been fascinated by the cyclopropane subunit.1 The smallest cycloalkane is found as a basic structural element in a wide range of naturally occurring compounds.2 Moreover, many cyclopropane-containing unnatural products have been prepared to test the bonding features of this class of highly strained cycloalkanes3 and to study enzyme mechanism or inhibition.4 Cyclopropanes have also been used as versatile synthetic intermediates in the synthesis of more functionalized cycloalkanes5,6 and acyclic compounds.7 In recent years, most of the synthetic efforts have focused on the enantioselective synthesis of cyclopropanes.8 This has remained a challenge ever since it was found that the members of the pyrethroid class of compounds were effective insecticides.9 New and more efficient methods for the preparation of these entities in enantiomerically pure form are still evolving, and this review will focus mainly on the new methods that have appeared in the literature since 1989. It will elaborate on only three types of stereoselective cyclopropanation reactions from olefins: the halomethylmetal-mediated cyclopropanation reactions (eq 1), the transition metal-catalyzed decomposition of diazo compounds (eq 2), and the nucleophilic addition-ring closure sequence (eqs 3 and 4). These three processes will be examined in the context of diastereoand enantiocontrol. In the last section of the review, other methods commonly used to make chiral, nonracemic cyclopropanes will be briefly outlined.