Gallium Trihalide Catalyzed Sequential Addition of Two Different Carbon Nucleophiles to Esters by Using Silyl Cyanide and Ketene Silyl Acetals

Yoshihiro Inamoto; Yuta Kaga; Yoshihiro Nishimoto; Makoto Yasuda; Akio Baba

doi:10.1002/chem.201403734

ChemInform Abstract: Gallium Trihalide Catalyzed Sequential Addition of Two Different Carbon Nucleophiles to Esters by Using Silyl Cyanide and Ketene Silyl Acetals.

ChemInform ◽

10.1002/chin.201510102 ◽

2015 ◽

Vol 46 (10) ◽

pp. no-no

Author(s):

Yoshihiro Inamoto ◽

Yuta Kaga ◽

Yoshihiro Nishimoto ◽

Makoto Yasuda ◽

Akio Baba

Keyword(s):

Carbon Nucleophiles ◽

Sequential Addition ◽

Silyl Acetals

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Enantiodivergent Formation of C–P Bonds: Synthesis of P-Chiral Phosphines and Methyl-phosphonate Oligonucleotides

10.26434/chemrxiv.11639985.v1 ◽

2020 ◽

Author(s):

Dongmin Xu ◽

Nazaret Rivas-Bascón ◽

Natalia M. Padial ◽

Kyle W. Knouse ◽

Bin Zheng ◽

...

Keyword(s):

Chemical Space ◽

Building Blocks ◽

Stereospecific Synthesis ◽

Methyl Group ◽

Carbon Nucleophiles ◽

Sequential Addition ◽

Chiral Phosphines ◽

Limonene Oxide ◽

Absolute Stereochemistry ◽

Nucleophile Addition

<p>A simple limonene-derived P(V)-based reagent for the modular, scalable, and stereospecific synthesis of chiral phosphines and methyl-phosphonate oligonucleotide (MPO) building blocks is presented. Built on a translimonene oxide (TLO) core, this formally triply electrophilic reagent class displays starkly differing reactivity from the cis-limonene oxide derived reagents reported previously [dubbed phosphorus-sulfur incorporation reagents or Ψ (PSI) for short]. These new phosphorus-incorporation reagents (PI, abbreviated as Π) access distinctly different chemical space than Ψ. The P(V)-manifold disclosed herein permits the stereochemically controlled sequential addition of carbon-based nucleophiles (from one to three) to produce a variety of enantiopure C–P bearing building blocks. When three carbon nucleophiles are added, useful P-chiral phosphines can be accessed after stereospecific reduction. When a single methyl group is added, the remaining nucleophiles can be nucleosides thus opening the door to the first stereospecific access to MPO-based oligonucleotide building blocks. Although both enantiomers of Π are available, only one isomer is required as the order of nucleophile addition controls the absolute stereochemistry of the final product through a unique enantiodivergent design.</p>

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Enantiodivergent Formation of C–P Bonds: Synthesis of P-Chiral Phosphines and Methyl-phosphonate Oligonucleotides

10.26434/chemrxiv.11639985 ◽

2020 ◽

Author(s):

Dongmin Xu ◽

Nazaret Rivas-Bascón ◽

Natalia M. Padial ◽

Kyle W. Knouse ◽

Bin Zheng ◽

...

Keyword(s):

Chemical Space ◽

Building Blocks ◽

Stereospecific Synthesis ◽

Methyl Group ◽

Carbon Nucleophiles ◽

Sequential Addition ◽

Chiral Phosphines ◽

Limonene Oxide ◽

Absolute Stereochemistry ◽

Nucleophile Addition

<p>A simple limonene-derived P(V)-based reagent for the modular, scalable, and stereospecific synthesis of chiral phosphines and methyl-phosphonate oligonucleotide (MPO) building blocks is presented. Built on a translimonene oxide (TLO) core, this formally triply electrophilic reagent class displays starkly differing reactivity from the cis-limonene oxide derived reagents reported previously [dubbed phosphorus-sulfur incorporation reagents or Ψ (PSI) for short]. These new phosphorus-incorporation reagents (PI, abbreviated as Π) access distinctly different chemical space than Ψ. The P(V)-manifold disclosed herein permits the stereochemically controlled sequential addition of carbon-based nucleophiles (from one to three) to produce a variety of enantiopure C–P bearing building blocks. When three carbon nucleophiles are added, useful P-chiral phosphines can be accessed after stereospecific reduction. When a single methyl group is added, the remaining nucleophiles can be nucleosides thus opening the door to the first stereospecific access to MPO-based oligonucleotide building blocks. Although both enantiomers of Π are available, only one isomer is required as the order of nucleophile addition controls the absolute stereochemistry of the final product through a unique enantiodivergent design.</p>

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The Inhibition of Platelet Aggregation by an Aorta Intima Extract

Thrombosis and Haemostasis ◽

10.1055/s-0038-1647710 ◽

1974 ◽

Vol 32 (02/03) ◽

pp. 417-431 ◽

Cited By ~ 14

Author(s):

A. du P Heyns ◽

D. J van den Berg ◽

G. M Potgieter ◽

F. P Retief

Keyword(s):

Platelet Aggregation ◽

Degradation Products ◽

Adenosine Diphosphate ◽

Inhibitory Effect ◽

Protective Role ◽

Vascular Trauma ◽

Wear And Tear ◽

Sequential Addition ◽

Aggregation Activity

SummaryThe platelet aggregating activity of extracts of different layers of the arterial wall was compared to that of Achilles tendon. Arterial media and tendon extracts, adjusted to equivalent protein content as an index of concentration, aggregated platelets to the same extent but an arterial intima extract did not aggregate platelets. Platelet aggregation induced by collagen could be inhibited by mixing with intima extract, but only to a maximum of about 80%. Pre-mixing adenosine diphosphate (ADP) with intima extracts diminished the platelet aggregation activity of the ADP. Depending on the relationship between ADP and intima extract concentrations aggregating activity could either be completely inhibited or inhibition abolished. Incubation of ADP with intima extract and subsequent separation of degradation products by paper chromatography, demonstrated a time-dependent breakdown of ADP with AMP, adenosine, inosine and hypoxanthine as metabolic products; ADP removal was complete. Collagen, thrombin and adrenaline aggregate platelets mainly by endogenous ADP of the release reaction. Results of experiments comparing inhibition of aggregation caused by premixing aggregating agent with intima extract, before exposure to platelets, and the sequential addition of first the intima extract and then aggregating agent to platelets, suggest that the inhibitory effect of intima extract results from ADP breakdown. It is suggested that this ADP degradation by intima extract may play a protective role in vivo by limiting the size of platelet aggregates forming at the site of minimal “wear and tear” vascular trauma.

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Synthesis of Allenyl Ketones by the Palladium-Catalyzed Carbonylation of 2-Alkynyl Carbonates in the Presence of Soft Carbon Nucleophiles

Synlett ◽

10.1055/s-1991-20842 ◽

1991 ◽

Vol 1991 (09) ◽

pp. 697-698 ◽

Cited By ~ 1

Author(s):

Tadakatsu Mandai ◽

Hiroaki Kunitomi ◽

Kiyoto Higashi ◽

Mikio Kawada ◽

Jiro Tsuji

Keyword(s):

Carbon Nucleophiles ◽

Palladium Catalyzed ◽

Soft Carbon

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Nickel-Catalyzed Regioselective Hydroalkylation of 1,3-Dienes with Hydrazones

10.26434/chemrxiv.8266643.v1 ◽

2019 ◽

Author(s):

Leiyang Lv ◽

Dianhu Zhu ◽

Zihang Qiu ◽

Jianbin Li ◽

Chao-Jun Li

Keyword(s):

Catalytic Method ◽

Unsaturated Hydrocarbons ◽

Carbon Nucleophiles ◽

Aryl Aldehydes ◽

Aldehydes And Ketones ◽

Sterically Hindered

Hydroalkylation of unsaturated hydrocarbons with unstablized carbon nucleophiles is difficult and remains a major challenge. The disclosed examples so far mainly focused on the involvement of heteroatom and/or stabilized carbon nucleophiles as efficient reaction partners. Reported here is an unprecedented regioselective nickel-catalyzed hydroalkylation of 1,3-dienes with hydrazones, generated in situ from abundant aryl aldehydes and ketones and acted as both the sources of unstabilized carbanions and hydride. With this strategy, both terminal and sterically hindered internal dienes are hydroalkylated efficiently in a highly selective manner, thus providing a novel and reliable catalytic method to construct challenging C(sp3)-C(sp3) bonds.

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