Pt-Catalyzed Enantioselective Diboration of Terminal Alkenes with B<sub>2</sub>(pin)<sub>2</sub>

Kliman, Laura T.; Mlynarski, Scott N.; Morken, James P.

doi:10.1021/ja9047762

Cited by 183 publications

(56 citation statements)

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“…In contrast to related transformations of monoalkynes, [29] monitoring the reaction progress by multinuclear NMR spectroscopy revealed the gradual disappearance of the starting materials, and the formation of two distinct compounds in benzene solution at elevated temperatures. Both species feature similar resonances in the 1 H, 11 B, and 13 C NMR spectra, which we rationalized by the generation of diastereomeric species. Complexes 4 and 5 were eventually isolated after workup as orange, moderately moisture-sensitive powders.…”

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confidence: 59%

“…Along with hydroboration, [1][2][3][4] transition-metalcatalyzed diboration [5] has become useful for the functionalization of unsaturated organic compounds. [6,7] This reaction is widely applicable to substrates such as alkynes [8,9] arynes, [10] alkenes, [11][12][13] carbenoids, [14,15] as well as diazo [16] and carbonyl compounds. [17][18][19][20] Although bis(catecholato)diborane(4) and bis(pinacolato)diborane(4) represent by far the most commonly employed diborane(4) species, the reaction is not restricted to their use.…”

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confidence: 99%

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Unexpected Generation of Diastereomers by Double Diboration of a Dialkyne

Bauer

Braunschweig

Gruß

et al. 2011

Chemistry A European J

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During the last two decades, boron compounds have become established as versatile reagents in organic synthesis, and different methods have been developed for their preparation. Along with hydroboration, [1][2][3][4] transition-metalcatalyzed diboration [5] has become useful for the functionalization of unsaturated organic compounds. [6,7] This reaction is widely applicable to substrates such as alkynes [8,9] arynes, [10] alkenes, [11][12][13] carbenoids, [14,15] as well as diazo [16] and carbonyl compounds. [17][18][19][20] Although bis(catecholato)diborane(4) and bis(pinacolato)diborane(4) represent by far the most commonly employed diborane(4) species, the reaction is not restricted to their use. For instance, several diboranes(4) with interesting properties are derived from [2]borametalloarenophanes. The first example of this class of organometallic compound, the [2]boraferrocenophane 1, was prepared by Herberhold, Wrackmeyer and co-worker, [21] while the molecular structure along with an alternative synthesis was published by our group.[22] Subsequently, a series of [2]borametalloarenophanes has appeared. [23-28b] These ansa complexes show tilted molecular structures, thus featuring significant molecular strain. In 2006, we successfully exploited this ring strain in oxidative addition reactions of [2]borametalloarenophanes to low-valent platinum centers, affording[3]diboraplatinametalloarenophanes. In addition, we demonstrated the suitability of [2]borametalloarenophanes as diboranes(4) in the platinum-mediated diboration of alkynes to form [4]diboradicarbametalloarenophanes.[29] By expansion of this strategy, we also achieved the diboration of diazo compounds [16] and isocyanides.[30]Herein, we report on the two diastereomeric [4]diboradicarbaferrocenophanes 4 and 5, which were obtained by double diboration of the conjugated dialkyne 3 either by a platinum-mediated route employing the [2]boraferrocenophane 1 in the presence of [PtA C H T U N G T R E N N U N G (PEt 3 ) 3 ], or stoichiometrically by using the [3]diboraplatinaferrocenophane 2, directly (Scheme 1). In contrast to related transformations of monoalkynes, [29] monitoring the reaction progress by multinuclear NMR spectroscopy revealed the gradual disappearance of the starting materials, and the formation of two distinct compounds in benzene solution at elevated temperatures. Both species feature similar resonances in the 1 H, 11 B, and 13 C NMR spectra, which we rationalized by the generation of diastereomeric species. Complexes 4 and 5 were eventually isolated after workup as orange, moderately moisture-sensitive powders. The NMR spectroscopic data of both diastereomers are fully consistent with the presence of doubly bis(borylated), conjugated triene systems bearing two ferro-

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confidence: 59%

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confidence: 99%

Unexpected Generation of Diastereomers by Double Diboration of a Dialkyne

Bauer

Braunschweig

Gruß

et al. 2011

Chemistry A European J

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“…When we subjected model substrate 32 to the conditions described in the study of Morken's group, 42 we observed the syn product with complete selectivity by 13 C-NMR spectroscopy (Fig. 6, ESI †).…”

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confidence: 94%

Total synthesis, stereochemical elucidation and biological evaluation of Ac₂SGL; a 1,3-methyl branched sulfoglycolipid from Mycobacterium tuberculosis

et al. 2013

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Total synthesis, stereochemical elucidation and biological evaluation of Ac(2)SGL; a 1,3-methyl branched sulfoglycolipid from Mycobacterium tuberculosis Geerdink, Danny; ter Horst, Bjorn; Lepore, Marco; Mori, Lucia; Puzo, Germain; Hirsch, Anna; Gilleron, Martine; de Libero, Gennaro; Minnaard, Adriaan IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from it. Please check the document version below. Document Version Publisher's PDF, also known as Version of record Publication date: 2012Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Geerdink, D., ter Horst, B., Lepore, M., Mori, L., Puzo, G., Hirsch, A. K. H., ... Minnaard, A. J. (2012). Total synthesis, stereochemical elucidation and biological evaluation of Ac(2)SGL; a 1,3-methyl branched sulfoglycolipid from Mycobacterium tuberculosis. Chemical Science, 4(2), 709-716. DOI: 10.1039/c2sc21620e Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. Mycobacterium tuberculosis, the causative agent of tuberculosis (TB), continues to represent a challenging pathogen causing many deaths. A reason for the persistence of this pathogen is the cell-envelope composition, which consists of long-tailed (glyco)lipids, involved in the modulation of the host immune response. Diacylated sulfoglycolipid Ac 2 SGL (1), found in the cell envelope, is a potent antigen that stimulates the immune response towards TB. This observation suggests the application of 1 as part of a vaccine. Here, we report the first asymmetric total synthesis of 1. Two approaches were developed for the synthesis of hydroxyphthioceranic acid (4), its polypropionate part, thereby establishing the absolute stereochemistry of the C17 hydroxyl function to be of (R)-configuration. Subsequently, 4 was regioselectively connected to the trehalose core and after selective sulfation and a final fourfold deprotection step, pure 1 was obtained. The identity of synthetic and natural 1 was confirmed by NMR and mass analysis, Furthermore, synthetic 1 shows identical biological function to 1 and activates CD1b-restricted and Ac 2 SGL-specific T cells that are highly sensitive to minimal structural modifications of 1 with the same potency. A modeling study is presented to point out the structural features of 1 that are important for binding to the antigen-presenting molecule CD1b and to the T-cell receptor. IntroductionTuber...

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“…66,67 Diborations have been well developed with transition metal catalysts. [68][69][70] They are useful transformations for the introduction of new functional groups into a molecule.…”

Section: Diborationmentioning

confidence: 99%

Synthesis, Structure, and Catalytic Studies of Palladium and Platinum Bis-Sulfoxide Complexes

Drinkel

Linden

et al. 2013

Organometallics

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The bis-sulfoxide ligand p-tolyl-binaso and its derivatives can be used to synthesize neutral and cationic palladium and platinum complexes. Various Pt bis-sulfoxide complexes could be made by using the precursor Pt(M,SS,SS)-p-tolyl-binasoCl2 (5a) and abstracting the chlorides with silver salts. The Pd analogue of this compound (4) could not be used in the same way. In this case, the sulfoxides appear to be very weakly coordinated and different methods to make stable Pd bis-sulfoxide complexes had to be found. The nature of the bonding in the synthesized compounds was studied through analysis of their IR and NMR spectra and X-ray crystal structures. These studies revealed that the trans effect of other ligands in the complex is quite significant in determining the lability of the metal-sulfoxide bond. Some of the more stable platinum structures were then tested for their activity as catalysts in hydroboration and diboration reactions. AbstractThe bissulfoxide ligand, p-tolyl-binaso and its derivatives can be used to synthesize neutral and cationic palladium and platinum complexes. Various Pt bissulfoxide complexes could be made by using the precursor Pt{(M,S S ,S S )-p-tolyl-binaso}Cl 2 (5a) and abstracting the chlorides with silver salts. The Pd analogue of this compound (4) could not be used in the same way. In this case, the sulfoxides appear to be very weakly coordinated and different methods to make stable Pd bissulfoxide complexes had to be found. The nature of the bonding in the synthesized compounds was studied through analysis of their IR and NMR spectra and X-ray crystal structures. These studies revealed that the trans-effect of other ligands in the complex is quite significant in determining the lability of the metal-sulfoxide bond. Some of the more stable platinum structures were then tested for their activity as catalysts in hydroboration and diboration reactions.

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Pt-Catalyzed Enantioselective Diboration of Terminal Alkenes with B₂(pin)₂

Cited by 183 publications

References 39 publications

Unexpected Generation of Diastereomers by Double Diboration of a Dialkyne

Unexpected Generation of Diastereomers by Double Diboration of a Dialkyne

Total synthesis, stereochemical elucidation and biological evaluation of Ac₂SGL; a 1,3-methyl branched sulfoglycolipid from Mycobacterium tuberculosis

Synthesis, Structure, and Catalytic Studies of Palladium and Platinum Bis-Sulfoxide Complexes

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Pt-Catalyzed Enantioselective Diboration of Terminal Alkenes with B2(pin)2

Cited by 183 publications

References 39 publications

Unexpected Generation of Diastereomers by Double Diboration of a Dialkyne

Unexpected Generation of Diastereomers by Double Diboration of a Dialkyne

Total synthesis, stereochemical elucidation and biological evaluation of Ac2SGL; a 1,3-methyl branched sulfoglycolipid from Mycobacterium tuberculosis

Synthesis, Structure, and Catalytic Studies of Palladium and Platinum Bis-Sulfoxide Complexes

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Pt-Catalyzed Enantioselective Diboration of Terminal Alkenes with B₂(pin)₂

Total synthesis, stereochemical elucidation and biological evaluation of Ac₂SGL; a 1,3-methyl branched sulfoglycolipid from Mycobacterium tuberculosis