Transition Metal-Mediated Polymerization of Isocyanides

Suginome, Michinori; Ito, Yoshihiko

doi:10.1007/b95531

Cited by 155 publications

(124 citation statements)

References 99 publications

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“…27 We now report the isolation and structural characterization of a series of compounds arising from the insertion reactions of the simplest isocyanide, MeNC, with the germylene Ge(Ar Me 6) 2 (Ar Me 6 = C6H3-2,6(C6H2-2,4,6-Me3)2) 28 and supply details of the mechanism of the subsequent transformation. We show that the simple adduct (Ar Me 6) 2GeCNMe (1), is formed in the first instance, whereupon the coordinated methylisocyanide molecule in 1 then undergoes a spontaneous migratory insertion into one of the Ge -C(Ar) bonds to form the structural isomer (Ar Me 6)Ge(μ-CNMe)(Ar Me 6) (1′ in hexane (20 mL) methylisocyanide (5 mmol) was added at room temperature. The purple color of the solution became yellow, and the reaction mixture was allowed to stir at room temperature for two days, whereupon the color of the solution changed to deep red.…”

Section: Scheme 1 Transition Metal Mediated Coupling Of Isocyanidesmentioning

confidence: 98%

“…[1][2][3][4] In particular, the synthesis of heterocycles resulting from coupling and cycloaddition reactions of isocyanides with other hetero-element unsaturated species is a widely-used technique. 5 Groundbreaking work by Passerini 6 and Ugi [7][8][9] led to a dramatic expansion of the study of cyanide and isocyanide coupling chemistry, most notably their metal catalyzed oligomerization and polymerization reactions.…”

Section: Introductionmentioning

confidence: 99%

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Mechanistic Study of Stepwise Methylisocyanide Coupling and C–H Activation Mediated by a Low-Valent Main Group Molecule

et al. 2013

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Section: Scheme 1 Transition Metal Mediated Coupling Of Isocyanidesmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Mechanistic Study of Stepwise Methylisocyanide Coupling and C–H Activation Mediated by a Low-Valent Main Group Molecule

et al. 2013

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“…Due to their formally divalent terminal carbon atom, isocyanides are unique organic nitrogen derivatives. Consequently, they have found wide use in organic synthesis, [7] especially in multicomponent reactions, [8] different types of insertions [9,10] and cycloadditions, [11] giving rise to a large variety of nitrogen-containing compounds. Cycloadditions are possible due to the ability of substituted methyl isocyanides to be metallated in the a-position, as first observed by Schçllkopf and Gerhart.…”

Section: Introductionmentioning

confidence: 99%

Oligosubstituted Pyrroles Directly from Substituted Methyl Isocyanides and Acetylenes

Lygin

Larionov

Korotkov

et al. 2008

Chemistry A European J

101

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The formal cycloaddition of alpha-metallated methyl isocyanides 1 onto the triple bond of electron-deficient acetylenes 2 represents a direct and convenient approach to oligosubstituted pyrroles 3. The scope and limitations of this reaction (24 examples, 25-97% yield) are reported along with an optimization of the reaction conditions and a rationalization of the mechanism. In addition, a related newly developed Cu(I)-mediated synthesis of 2,3-disubstituted pyrroles by the reaction of copper acetylides derived from unactivated terminal alkynes with substituted methyl isocyanides is described (11 examples, 5-88% yield).

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“…Either static or dynamic helical polymers with an excess one-handedness, such as poly(quinoxaline-2,3-diyl)s (4), 25,26 polyguanidines (5), 27,28 poly(phenyl isocyanide)s (6) 29,30 and polyacetylenes (7), [8][9][10][11][12][31][32][33][34] have also been prepared by the polymerization of analogous monomers bearing different chiral or achiral substituents, that is, the boundary between static and dynamic helical conformations is totally dependent on the helix inversion barrier. In addition, the helical conformations of dynamic helical polymers can be locked, resulting in static helical polymers as demonstrated by the memory effect of induced helical poly(phenylacetylene)s (7) 35 and poly(4-carboxyphenyl isocyanide) (6: R¼COOH).…”

mentioning

confidence: 99%

“…30 The details of their pioneering studies have been thoroughly reviewed elsewhere. [1][2][3][4][5][6][7][8][9][10][11][12]25,31,34 Although various helical polymers have been synthesized, particularly in the last decade, their exact helical structures, including helical pitch and helical sense (right-or left-handed helix), remain unsolved. The preferred-handed helix formation of most synthetic helical polymers has usually been based on circular dichroism (CD) and/or optical rotation measurements, which, however, may not be straightforward for proposing an unambiguous helical structure.…”

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confidence: 99%

Synthesis and structure determination of helical polymers

Yashima

2010

Polym J

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During the last decade, remarkable progress in developing synthetic helical polymers with a controlled helical sense has been achieved. However, the exact helical structures of most of the already prepared synthetic helical polymers remain unsolved. In this review, the recent progress in the synthesis of helical polymers and their structural determination, including helical pitch and handedness based on X-ray diffraction and spectroscopic measurements, together with high-resolution atomic force microscopy, is described. Polymer Journal (2010) 42, 3-16; doi:10.1038/pj.2009 Keywords: atomic force microscopy; circular dichroism; helical polymer; helical structure; X-ray diffractionThe helix is a unique structure as observed in nature from microscopic to macroscopic levels and is inherently chiral. Inspired by biological helices, such as DNA and proteins, chemists have been challenged to synthesize helical polymers with a controlled helical sense that aims not only to mimic biological helical structures but also to develop chiral materials for the separation of enantiomers and asymmetric catalysis. [1][2][3][4][5][6][7][8][9][10][11][12] The history of synthetic helical polymers with optical activity extends back to the 1960s when Pino and Lorenzi 13 investigated the structural and chiroptical properties of isotactic vinyl polymers prepared by the polymerization of a-olefins bearing optically active substituents. Although helical polyolefins are totally dynamic in nature and consist of short helical segments separated by frequently occurring helical reversals among disordered, random coil conformations, 14 this study was significant in the field of synthetic helical polymers, from which a number of helical polymers have been synthesized.On the basis of the pioneering studies by Nolte et al., 15 Okamoto et al. 16 and Green et al., 17 the existing synthetic helical polymers that exhibit an optical activity solely because of their macromolecular helicity can be classified into two categories with respect to their helix inversion barriers, that is, static and dynamic helical polymers (Figure 1). 9,12 Optically active helical polymers, such as poly(triphenylmethyl methacrylate) (1), 16 poly(t-butyl isocyanide) (2) 15 and polychloral (3), 18 have a sufficiently high helix inversion barrier and belong to the family of static helical polymers. Therefore, these helical polymers with either a right-or left-handed helix can be prepared by the helix-sense-selective polymerization of the corresponding achiral monomers using chiral catalysts or initiators under kinetic control. On the other hand, dynamic helical polymers, such as polyisocyanates (8) 17 and polysilanes (9), 19 possess a very low helix inversion barrier.As a consequence, they consist of interconvertible right-and lefthanded helical segments separated by rarely occurring helical reversals, as demonstrated by Green et al.,6,20,21 so that a preferred-handed helical conformation can be induced in the presence of a small amount of chiral residues at the pendant 6 or ter...

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Transition Metal-Mediated Polymerization of Isocyanides

Cited by 155 publications

References 99 publications

Mechanistic Study of Stepwise Methylisocyanide Coupling and C–H Activation Mediated by a Low-Valent Main Group Molecule

Mechanistic Study of Stepwise Methylisocyanide Coupling and C–H Activation Mediated by a Low-Valent Main Group Molecule

Oligosubstituted Pyrroles Directly from Substituted Methyl Isocyanides and Acetylenes

Synthesis and structure determination of helical polymers

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