Iodine and Cymantrenyl Regioselective Exchange in the η5-IC5H4 (CO)2Fe-η1,η5-C5H4Mn(CO)3 Complex under Cross-Coupling Conditions.

Two types of immobilized on the amino-functionalized polystyrene-supported acyclic diaminocarbene palladium complexes (ADC-PdII) are investigated under Sonogashira cross-coupling conditions. Depending on substituents in the diaminocarbene fragment immobilized ADC-PdII, systems are found to have different catalytic activity and stability regarding Pd-leaching. PdII-diaminocarbenes possessing protons at both nitrogen atoms smoothly decompose into Pd0-containing species providing a catalytic “cocktail system” with high activity and ability to reuse within nine runs. Polymer-supported palladium (II) complex bearing NBn–Ccarbene–NH-moiety exhibits greater stability while noticeably lower activity under Sonogashira cross-coupling. Four molecular ADC-PdII complexes are also synthesized and investigated with the aim of confirming proposed base-promoted pathway of ADC-PdII conversion through carbodiimide into an active Pd0 forms.

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Towards triptycene functionalization and triptycene-linked porphyrin arrays

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.16.70 ◽

2020 ◽

Vol 16 ◽

pp. 763-777

Author(s):

Gemma M Locke ◽

Keith J Flanagan ◽

Mathias O Senge

Keyword(s):

Electron Transfer ◽

Single Crystal ◽

Cross Coupling ◽

X Ray ◽

Fluorescence Studies ◽

Coupling Conditions ◽

Porphyrin Dimer

Herein, 9,10-diethynyltriptycene is investigated for its use as a rigid isolating unit in the synthesis of multichromophoric arrays. Sonogashira cross-coupling conditions are utilized to attach various porphyrins and boron dipyrromethenes (BODIPYs) to the triptycene scaffold. While there are previous examples of triptycene porphyrin complexes, this work reports the first example of a linearly connected porphyrin dimer, linked through the bridgehead carbons of triptycene. Symmetric and unsymmetric examples of these complexes are demonstrated and single crystal X-ray analysis of an unsymmetrically substituted porphyrin dimer highlights the evident linearity in these systems. Moreover, initial UV–vis and fluorescence studies show the promise of triptycene as a linker for electron transfer studies, showcasing its isolating nature.

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Ten years advancement in the synthetic applications of 2-bromo-cyclohexenecarbaldehydes and 2-bromobenzaldehydes and derived substrates under palladium-catalyzed cross-coupling conditions

Tetrahedron ◽

10.1016/j.tet.2017.05.053 ◽

2017 ◽

Vol 73 (27-28) ◽

pp. 3731-3799 ◽

Cited By ~ 3

Author(s):

Munmun Ghosh ◽

Jayanta K. Ray

Keyword(s):

Cross Coupling ◽

Coupling Conditions ◽

Palladium Catalyzed

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Unusual Regioselective Reactions of 2,4-Bis(methylsulfanyl)pyrimidine under Modified Suzuki and Stille Cross-Coupling Conditions

Synthesis ◽

10.1055/s-0031-1289615 ◽

2011 ◽

Vol 44 (01) ◽

pp. 120-124 ◽

Cited By ~ 2

Author(s):

David Boykin ◽

Abdelbasset Farahat

Keyword(s):

Cross Coupling ◽

Coupling Conditions ◽

Regioselective Reactions

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Total Synthesis of Tiacumicin B: Implementing H-bond-Directed Acceptor Delivery for Highly Selective beta-Glycosylations

10.26434/chemrxiv.11371749.v1 ◽

2019 ◽

Author(s):

Stephanie Norsikian ◽

cedric Tresse ◽

Marc François-Eude ◽

Louis Jeanne-Julien ◽

Guillaume Masson ◽

...

Keyword(s):

Total Synthesis ◽

Cross Coupling ◽

Biological Properties ◽

Ring Size ◽

Efficient Removal ◽

Coupling Conditions ◽

Intestinal Infections ◽

Protective Groups ◽

Leaving Groups ◽

Total Beta

We report a total synthesis of tiacumicin B, one of the most structurally complex natural antibiotic macrolides. Endowed with remarkable biological properties, it is used to treat very severe intestinal infections. The strategy is in part based on our experience of the synthesis of the tiacumicin B aglycone, and on the decisive implementation of an H-bond-mediated Aglycone Delivery (HAD) using sulfoxides as anomeric leaving-groups. This new HAD variant permitted highly beta-selective rhamnosylation and noviosylation. To increase the convergence, the rhamnosylated C1-C3 fragment thus obtained was anchored to the C4-C19 aglycone fragment by adapting the reliable Suzuki-Miyaura cross-coupling conditions used for the aglycone synthesis. The ring-size selective macrolactonization provided a compound engaged directly in the noviolysation step with a virtually total beta-selectivity. The final and efficient removal of all the protective groups (PGs) provided synthetic tiacumicin B.

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Total Synthesis of Tiacumicin B: Implementing H-bond-Directed Acceptor Delivery for Highly Selective beta-Glycosylations

10.26434/chemrxiv.11371749 ◽

2019 ◽

Author(s):

Stephanie Norsikian ◽

cedric Tresse ◽

Marc François-Eude ◽

Louis Jeanne-Julien ◽

Guillaume Masson ◽

...

Keyword(s):

Total Synthesis ◽

Cross Coupling ◽

Biological Properties ◽

Ring Size ◽

Efficient Removal ◽

Coupling Conditions ◽

Intestinal Infections ◽

Protective Groups ◽

Leaving Groups ◽

Total Beta

We report a total synthesis of tiacumicin B, one of the most structurally complex natural antibiotic macrolides. Endowed with remarkable biological properties, it is used to treat very severe intestinal infections. The strategy is in part based on our experience of the synthesis of the tiacumicin B aglycone, and on the decisive implementation of an H-bond-mediated Aglycone Delivery (HAD) using sulfoxides as anomeric leaving-groups. This new HAD variant permitted highly beta-selective rhamnosylation and noviosylation. To increase the convergence, the rhamnosylated C1-C3 fragment thus obtained was anchored to the C4-C19 aglycone fragment by adapting the reliable Suzuki-Miyaura cross-coupling conditions used for the aglycone synthesis. The ring-size selective macrolactonization provided a compound engaged directly in the noviolysation step with a virtually total beta-selectivity. The final and efficient removal of all the protective groups (PGs) provided synthetic tiacumicin B.

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Ionic Liquid Supports Stable Under Conditions of Peptide Couplings, Deprotections and Traceless Suzuki Reactions

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20070417 ◽

2007 ◽

Vol 72 (3) ◽

pp. 417-434 ◽

Cited By ~ 5

Author(s):

Zoia Mincheva ◽

Fabien Bonnette ◽

Olivier Lavastre

Keyword(s):

Ionic Liquid ◽

Ionic Liquids ◽

Cross Coupling ◽

Amino Groups ◽

Peptide Chemistry ◽

Suzuki Reactions ◽

Coupling Conditions ◽

Pyridinium Cations

Ionic liquid supports (ILS) functionalized with carboxylic, alcoholic or amino groups were synthesized, based on 1-methylimidazolium and pyridinium cations, and bromide, chloride, iodide and tetrafluoroborate anions. These reactive ionic liquids were fully characterized by NMR and HRMS. Ionic liquids based on 1-(6-aminohexyl)-3-methylimidazolium iodide have been used in the conditions of peptide chemistry such as coupling and deprotection reactions. A method for attaching (bromophenyl)silanes to the ionic liquid supports was also developed to introduce traceless linkers. An ionic liquid with attached bromobenzene was reacted with ArB(OH)2 under the Suzuki cross-coupling conditions and the resulting compound was cleaved by bromodesilylation with Br2/pyridine to give the substituted products in good yields. The substrate loading of the ILS is high and can be tuned to between 2.5 and 5.0 mmol/g.

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