Acyl Cyanides Research Articles

Indium‐Mediated Coupling of Bromoacetonitriles with Aromatic Acyl Cyanides: Convenient Synthesis of Aromatic α‐Cyano Ketones.

AbstractFor Abstract see ChemInform Abstract in Full Text.

A new ytterbium iodide mediated coupling of acyl cyanides and synthesis of 1,2-diketones

Conversion of acyl cyanides 1 into 1,2-diketones 2 has been achieved by the action of ytterbium iodide in dry tetrahydrofuran at room temperature, in high yields.

Nitrile sulfides. Part 13.1 Synthesis of 5-acyl-1,2,4-thiadiazoles by cycloaddition of nitrile sulfides to acyl cyanides

Nitrile sulfides. Part 13.1 Synthesis of 5-acyl-1,2,4-thiadiazoles by cycloaddition of nitrile sulfides to acyl cyanides

A Click Chemistry Approach to Tetrazoles by Huisgen 1,3-Dipolar Cycloaddition: Synthesis of 5-Acyltetrazoles from Azides and Acyl Cyanides We thank the National Institute of General Medical Sciences, National Institutes of Health (GM-28384), the National Science Foundation (CHE-9985553), the Skaggs Institute for Chemical Biology for a Predoctoral Fellowship (Z.D.), and the W. M. Keck Foundation for financial support.

Klick-Chemie: Acylcyanide reagieren mit Alkylaziden in hohen Ausbeuten durch Erhitzen auf 120–130°C (siehe Schema). Die Reaktionen verlaufen lösungsmittelfrei, und die Aufarbeitung ist einfach. Im Fall von Cyanameisensäure-p-nitrophenylester als Dipolarophil sind die erhaltenen Tetrazole für weitere Funktionalisierungen aktiviert. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2001/2002/z18693_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

A Click Chemistry Approach to Tetrazoles by Huisgen 1,3-Dipolar Cycloaddition: Synthesis of 5-Acyltetrazoles from Azides and Acyl Cyanides We thank the National Institute of General Medical Sciences, National Institutes of Health (GM-28384), the National Science Foundation (CHE-9985553), the Skaggs Institute for Chemical Biology for a Predoctoral Fellowship (Z.D.), and the W. M. Keck Foundation for financial support.

Click chemistry: Acyl cyanides react with alkyl azides in high yield by heating at 120–130°C (see scheme). The reactions are run neat, and the workup is simple. When p-nitrophenyl cyanoformate is used as the dipolarophile, the resulting tetrazoles are activated for rapid functionalization as an activated ester.

Indium-mediated coupling of bromoacetonitriles with aromatic acyl cyanides: convenient synthesis of aromatic α-cyano ketones

Indium-mediated coupling of bromoacetonitrile and 2-bromopropionitrile with a variety of aromatic acyl cyanides afforded the corresponding aromatic α-cyano ketones in moderate to good yields under mild and neutral conditions.

The regioselective preparation of 1,3-diketones

The regioselectivity of the acylation of Li enolates and silyl enol ethers is reported using acyl halides and acyl cyanides. We illustrate a simple method for the preparation of 1,3-diketones via the silyl enol ether in excellent yields, free from competing O-acylation and diacylation products.

INDIUM-MEDIATED ALLYLATION OF ACYL CYANIDES IN AQUEOUS MEDIA: A CONVENIENT SYNTHESIS OF β,γ-UNSATURATED KETONES

ABSTRACT The indium-mediated allylation reaction of acyl cyanides with allyl halides in aqueous media afforded a variety of β,γ-unsaturated ketones in moderate to good yields under mild and neutral conditions.

ChemInform Abstract: Indium‐Mediated Highly Regioselective Reaction of Prop‐2‐ynyl Bromides with Acyl Cyanides in Aqueous Media: A Convenient Synthesis of Allenic and Propargylic Ketones.

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Femtosecond probing of photodissociation dynamics in acyl cyanides

The photodissociation of two acyl cyanide compounds, R–C(O)–CN, where R=methyl and tert-butyl groups, has been investigated using femtosecond time-resolved laser-induced fluorescence (LIF) spectroscopy. Both compounds were excited by two-photon excitation at a total energy of ∼6.4 eV and the formation of the free CN(X) radical products was probed in real time by monitoring the CN X→B LIF signal. The results revealed that the temporal evolution of the CN(X) formation can be well characterized by delayed biexponential rise functions with time constants in the picosecond time scale, indicating that the dissociation occurs via a complex-mode mechanism. We proposed a dissociation mechanism involving two discernable stages to account for the observed temporal behaviors as well as previous photofragment translational spectroscopic results reported by other groups. Our analyses suggested that the selectivity between the C–CN and C–R bond cleavage is determined by the competition between the adiabatic and nonadiabatic dynamics of the S2 state. The results also indicated that the adiabatic dissociation process occurring on the S2 surface is not statistical. We speculate that this nonstatistical dissociation behavior is due to an initial nonuniform phase space distribution and a slow intramolecular vibrational energy redistribution process that prevents the system from sampling the entire phase space before the reaction completes.

Studies on enolate chemistry of 8-thiabicyclo[3.2.1]- octan-3-one: enantioselective deprotonation and synthesis of sulfur analogs of tropane alkaloids

Enantioselective deprotonation of 8-thiabicyclo[3.2.1]octan-3-one (1) with chiral lithium amides, followed by reactions with electrophiles affords sulfur analogs of tropane alkaloids of pyranotropane family. Thus, deprotonation of 1 with (S)-N-(diphenyl)methyl-1-phenylethylamine (11d), followed by the reaction of the resulting nonracemic enolate with benzaldehyde gives the corresponding aldol product as one diastereoisomer (exo, threo) and in high enanatiomeric purity (95% ee). Trimethylsilyl chloride, acetic anhydride, and acyl cyanides react readily with the lithium enolate to give the corresponding derivatives of 1, however common alkylating agents fail to provide C-alkylated products. The reaction with acyl cyanides derived from α,β-unsaturated carboxylic acids (e.g., cinnamoyl cyanide) can be utilized in synthesis of thia-analogs of tropane alkaloids physoperuvine and isobellendine (13, 15).Key words: enantioselective deprotonation, tropane alkaloids.

Indium-mediated highly regioselective reaction of prop-2-ynyl bromides with acyl cyanides in aqueous media: a convenient synthesis of allenic and propargylic ketones

Indium-mediated reaction of acyl cyanides 1 with prop-2-ynyl bromides 2 in aqueous media occurs regioselectively to afford either allenic 3 or propargylic ketones 4 depending on the γ-substituent of the prop-2-ynyl bromide under the mild conditions.

A Direct Observation of Non-RRKM Behavior in Femtosecond Photophysically Activated Reactions

A nonstatistical behavior has been observed in the photodissociation of two acyl cyanide compounds, R-C(O)-CN, where R = methyl and tert-butyl groups. The initial activation was achieved by femtosecond two-photon excitation followed by ultrafast internal conversion. The excited-state dissociation dynamics was followed in real time by monitoring the temporal evolution of CN (X) products. The observed product appearance time constants are in picosecond time scales and are markedly similar for the two compounds studied. Our analyses revealed that the excited-state dissociation rate does not decrease with molecular size as much as statistical rate theory predicts, suggesting a nonergodic system in which the available vibrational energy does not redistributed statistically among all modes before the bond breakage occurs.

Indium-mediated reductive coupling of acyl cyanides: a convenient synthesis of 1,2-diketones

The indium-mediated reductive coupling of acyl cyanides afforded the corresponding 1,2-diketones in moderate to good yields under neutral and mild conditions.

An efficient synthesis of dinitrile derivatives by the reaction of oxime esters or acid anhydrides with cyanotrimethylsilane catalyzed by La(O(i)()Pr)(3)

The reaction of oxime esters with cyanotrimethylsilane (Me(3)SiCN) under the influence of a catalytic amount of lanthanide compounds produced alpha-trimethylsilyloxydinitrile derivatives in excellent yields accompanied with the formation of trimethylsilyl oxime ethers. Among the lanthanoid catalysts examined, La(O(i)()Pr)(3) was found to be the best catalyst. The reaction seems to proceed through the formation of acyl cyanides as intermediates, followed by the addition of Me(3)SiCN to them. Additionally, the reaction of acetic anhydride with Me(3)SiCN catalyzed by La(O(i)()Pr)(3) gave 1-trimethylsilyloxyethane dinitrile. Thus, various alpha-trimethylsilyloxydinitriles were synthesized in good yields by allowing oxime esters or acid anhydrides to react with Me(3)SiCN in the presence of a catalytic amount of La(O(i)()Pr)(3).

A concise synthesis of topsentin A and nortopsentins B and D.

[reaction: see text] A concise synthesis of topsentin A (R(1) = R(2) = H) and nortopsentins B (R(1) = Br, R(2) = H) and D (R(1) = R(2) = H) is described from oxotryptamine 5 via reduction of acyl cyanide 4. Regiospecific bromination of 3-cyanoindole afforded 6-bromo-3-cyanoindole (10) as the major product.

Development of a Method for the Preparation of α-Azido-Masked Acyl Cyanides, Synthetic Equivalents of N-Protected– C-Activated α-Amino Acids

A method for the preparation of α-azido-masked acyl cyanides as synthetic equivalents of N-protected– C-activated α-amino acids was developed using carbon–carbon bond formation between aldehydes and the Masked Acyl Cyanide Reagents, followed by sulfonylation and substitution by azide anion. This method was applied to the synthesis of d-threonine and l- allo-threonine derivatives.

Synthesis of 1,3-Diketones by Reaction of α-Haloketones with Acyl Cyanides Promoted by Samarium Diiodide

α-Haloketones reacted with acyl cyanides to form 1,3-diketones in the presence of samarium diiodide. The reaction was assumed to proceed via a mechanism involving samarium enolates formed in situ from α-haloketones.

Enolates of Thiabicyclic Ketones as Stepping Stones Towards Synthesis of Sulfur Analogs of Tropane Alkaloids

Enantioselective deprotonation of the bicyclic, sulfur bridged ketone TBON (8-thiabicyclo[3.2.1]octan-3-one, 1) with chiral lithium amides is described. Enolization proceeds with high levels of selectivity with some bases (most notably with lithium (S)-N-diphenylmethyl-1-phenylethanamide 3d) and the subsequent reaction of the resulting non-racemic lithium enolate with acyl cyanides allows efficient synthesis of sulfur analogs of tropane alkaloids (e. g., compound 8).

Synthetic Utility of Organometallic Reagents Derived from Group IV Metal Tetrachlorides and CH3Li. A Direct Synthesis of 2-(2-Keto-1-alkylidene)tetrahydropyrroles from 4-Alkynylamines and Acyl Cyanides

The non-Cp-bearing titanium alkyls (CH3)2TiCl2·L2 (1a) and (CH3)2Ti(OTFE)Cl·L2 (1b) and their Zr(IV) analogues have been shown to mediate efficient aminoalkyne cyclizations to provide azatitanium intermediates that undergo facial C-acylation in the presence of acyl cyanides.