The Preparation and Pd(0)-Catalysed Cross Coupling Reactions of α-(Phenylthio)alkenylzinc Reagents

Pimm, A.; Kocieński, Philip; Street, S. D. A.

doi:10.1055/s-1992-21528

Cited by 49 publications

(13 citation statements)

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“…[104] Further reaction of 137 (R = H) with TTF (133) at an elevated temperature afforded [8]dendralene 138 (R = H), although in a low yield (21 %). Furthermore, adding a mixture of TCNE (129) and TTF (133) to the CN-substituted tetrayne 136 resulted in a cascade of successive TCNE and TTF cycloadditions to provide [8]dendralene 138 (R = CN) in a remarkably high yield (58 %) given the eight distinct processes occurring in this one-pot process. [105] To rationalize this amazing cascade of additions, the authors suggest that after the [2+2] cycloaddition of TCNE (129) to the substrate to provide the corresponding tetracyano-1,3-butadiene (TCBD) derivative, the triple bond next to this TCBD moiety is sufficiently electron deficient to participate in a subsequent [2+2] cycloaddition with 133.…”

Section: Acyclic Dendralene Derivativesmentioning

confidence: 99%

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Dendralenes Branch Out: Cross‐Conjugated Oligoenes Allow the Rapid Generation of Molecular Complexity

2012

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Twenty-seven years ago, H. Hopf published the only previous comprehensive review on branched oligoenes that had the title "Dendralenes: A Neglected Family of Hydrocarbons". The dendralenes are no longer neglected. Research into the synthesis, properties, and applications of dendralenes is rapidly gaining momentum and this Review summarizes important recent findings. From significant fundamental properties (the first demonstration of alternating behavior since the annulenes) through to unparalleled complexity-generating synthetic transformations, this fundamental oligoene family is coming of age. Effective synthetic approaches to cyclic and acyclic dendralene systems are analyzed and classified. The most powerful synthetic transformations of the dendralenes, diene-transmissive Diels-Alder reactions, are surveyed in detail.

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Section: Acyclic Dendralene Derivativesmentioning

confidence: 99%

“…173). [133,134] A more classical approach, involving 1,2-nucleophilic addition of an alkenylmetal to a conjugated enone 174 followed by regioselective dehydration (175 to 176) has also been employed. [135] Several reports of cross-coupling approaches to afford 4-(or 5-)alkenyl 2-pyrones (or 2-pyridones) have been published.…”

Section: Angewandte Chemiementioning

confidence: 99%

Dendralenes Branch Out: Cross‐Conjugated Oligoenes Allow the Rapid Generation of Molecular Complexity

2012

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“…It should be added that Zn salts can also serve as effective cocatalysts or promoters13 accelerating other Pd-catalyzed cross-coupling reactions involving Al,13 Zr,13 B,14 Cu,6 Sn,15 and so on.…”

Section: Introductionmentioning

confidence: 99%

Alkyne Elementometalation−Pd-Catalyzed Cross-Coupling. Toward Synthesis of All Conceivable Types of Acyclic Alkenes in High Yields, Efficiently, Selectively, Economically, and Safely: “Green” Way

et al. 2010

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Palladium-catalyzed cross-coupling reactions, especially those involving Zn, Al, Zr (Negishi coupling) and B (Suzuki coupling), collectively have brought about "revolutionary" changes in organic synthesis. Thus, two regio-and stereodefined carbon groups generated as R 1 M (M = Zn, Al, B, Cu, Zr, etc.) and R 2 X (X = I, Br, OTs, etc.) may now be cross-coupled to give R 1 -R 2 with essentially full retention of all structural features. For alkene syntheses, alkyne elementometalation reactions including hydrometalation (B, Al, Zr, etc.), carbometalation (Cu, Al-Zr, etc.), and haloboration (BX 3 where X is Cl, Br, and I) have proven to be critically important. Some representative examples of highly efficient and selective (≥98%) syntheses of di-, tri-and oligoenes containing regio-and stereodefined di-and trisubstituted alkenes of all conceivable types will be discussed with emphasis on those of natural products. Some interesting but undesirable cases involving loss of the initial structural identities of the alkenyl groups are attributable to the formation of allylpalladium species, which must be either tamed or avoided. Some such examples involving the synthesis of 1,3-, 1,4-, and 1,5-dienes will also be discussed.

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“…28 Comparable 3 J 1 H-119,117 Sn coupling constants (54.0 Hz for R = Me or Ph) could be observed. The 3 J 13 C- 119,117 Sn coupling constant was lower than expected (32.0 Hz), as in the case of alkoxyalkenyltin derivatives.…”

Section: Sulfur Substituentsmentioning

confidence: 96%

13C NMR Analysis as a Useful Tool for Structural Assignment of Vinyl- and Dienyltin Derivatives

Betzer¹,

Menez²,

Prunet³

et al. 2002

Synlett

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During the last decade, vinyl-and dienyltin derivatives have been extensively developed and used in organic synthesis. 1 H NMR analysis of these compounds was the first analytical tool employed, together with 119 Sn NMR, for the assignment of the E or Z stereochemistry of vinylstannyl derivatives. In this paper we want to show that 13 C NMR is a powerful tool for structural analysis of vinyl-and dienyltin compounds. Chemical shifts and 13 C-119-117 Sn coupling constants are reported for several examples. In all cases described, the 3 J 13 C -119-117 Sn values give the most definitive argument for structural assignment. 1 J, 2 J and 3 J 13 C-119-117 Sn coupling constants are also reported, along with the a, b, g, and d effects of the stannyl group. When the vinyltin function is functionalized with a heteroatomic substituant, some important changes occur in the chemical shifts and coupling constants. Some examples are given in the a-oxygen, -sulfur, -halogen, -silyl, and -tin substituted vinyltin series.In the course of total syntheses of natural products, new strategies have been developed for the construction of unsaturated fragments, which are based on the preparation of vinyl-, dienyl-, or trienyltin derivatives. These derivatives are later engaged in Sn/halogen exchange, Sn/Li transmetallation, or in cross-coupling palladium-catalyzed reactions. 1 The assignment of the E or Z stereochemistry of the stannyl derivatives can usually be resolved using spectroscopic methods such as NMR techniques, but information is often omitted or contained in footnotes or supplementary material of short papers, and thus is difficult to collect except in the case of 1 H or 119 Sn NMR data.It is well know that tin possesses three 1 / 2 spin isotopes, 115 Sn (0.3%), 117 Sn (7.5%) and 119 Sn (8.6%).Sn spin-spin coupling constants can be observed and measured. 2 119 Sn NMR is a powerful analytical tool, 3 giving tin atoms chemical shifts, which are typical of the nature of the tin atom substitution. However no structural proof can be deduced from these data, excepted for deuterium containing derivatives. 4In the case of alkyltin compounds, Singh by 1 H NMR measured the 1 J, 2 J, 3 J and 4 J 1 H-119,117 Sn NMR coupling constants. 5 In a 13 C NMR study, Kuivila et al. established a "Karplus-type" correlation between the value of 3 J 13 C- 119,117 Sn and the dihedral angle of the coupling nuclei.For vinyltin derivatives, the 1 J, 2 J, 3 J and 4 J 1 H-119,117 Sn coupling constants are also well known. The 3 J H-=-Sn which appears to be the most interesting argument for stereochemical assignment, by Leusink 6 clearly shows that 3 J H(Z)-=-Sn values vary from 75.0 to 50.0 Hz whereas the corresponding 3 J H(E)-=-Sn values range from 120.0 to 90.0 Hz (Figure 1). 7 In most cases, the values of 3 J H-=-Sn allows unambiguous structural determination for bprotonated vinylstannanes.However, the measurement of 3 J H-=-Sn coupling constants becomes difficult due to multiplicity of the signals and/or overlap between stannyl satellites and other s...

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The Preparation and Pd(0)-Catalysed Cross Coupling Reactions of α-(Phenylthio)alkenylzinc Reagents

Cited by 49 publications

References 0 publications

Dendralenes Branch Out: Cross‐Conjugated Oligoenes Allow the Rapid Generation of Molecular Complexity

Dendralenes Branch Out: Cross‐Conjugated Oligoenes Allow the Rapid Generation of Molecular Complexity

Alkyne Elementometalation−Pd-Catalyzed Cross-Coupling. Toward Synthesis of All Conceivable Types of Acyclic Alkenes in High Yields, Efficiently, Selectively, Economically, and Safely: “Green” Way

13C NMR Analysis as a Useful Tool for Structural Assignment of Vinyl- and Dienyltin Derivatives

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