ChemInform Abstract: Introduction of a Triflate Group into Sterically Hindered Positions in 1-Aryl-4,6-diamino-1,3,5-triazines and Their Dimroth Rearrangement Products.

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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Synthesis of Conjugated Triynes via Alkyne Metathesis

10.26434/chemrxiv.8342534.v2 ◽

2019 ◽

Author(s):

Idriss Curbet ◽

Sophie Colombel-Rouen ◽

Romane Manguin ◽

Anthony Clermont ◽

Alexandre Quelhas ◽

...

Keyword(s):

Steric Hindrance ◽

High Selectivity ◽

Alkyne Metathesis ◽

Cross Metathesis ◽

Synthetic Strategy ◽

Sterically Hindered ◽

Site Selective

<div> <div> <div> <div> <p>The synthesis of conjugated triynes by molybdenum-catalyzed alkyne metathesis is reported. Strategic to the success of this approach is the utilization of sterically-hindered diynes that allowed for the site- selective alkyne metathesis to produce the desired con- jugated triyne products. The steric hindrance of alkyne moiety was found to be crucial in preventing the for- mation of diyne byproducts. This novel synthetic strategy was amenable to self- and cross-metathesis providing straightforward access to the corresponding symmetrical and dissymmetrical triynes with high selectivity. </p> </div> </div> </div> </div>

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Dimroth Rearrangement-Old but not Outdated

Current Organic Chemistry ◽

10.2174/1385272821666170427125720 ◽

2017 ◽

Vol 21 (25) ◽

Cited By ~ 4

Author(s):

Anna Krajczyk ◽

Jerzy Boryski

Keyword(s):

Dimroth Rearrangement

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Synthesis of 4-Arylaminoquinazolines from 2-amino-N'-Arylbenzamidines and Orthoesters via the Dimroth Rearrangement of Intermediate Quinazolin-4(3H)- Imines

Current Organic Chemistry ◽

10.2174/1385272823666181126112958 ◽

2019 ◽

Vol 22 (28) ◽

pp. 2801-2808

Author(s):

Krzysztof Zemlak ◽

Wojciech Szczepankiewicz ◽

Bartłomiej Kula ◽

Tadeusz Bieg

Keyword(s):

Dimroth Rearrangement

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Synthesis of 2-amino-5,7-dimethyl-4-oxopyrido[3,4-e]-1,3-thiazines

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19833426 ◽

1983 ◽

Vol 48 (12) ◽

pp. 3426-3432 ◽

Cited By ~ 4

Author(s):

Dušan Koščík ◽

Pavol Kristian ◽

Ondrej Forgáč

Keyword(s):

Spectral Data ◽

Chlorine Atom ◽

Mass Spectra ◽

High Reactivity ◽

Secondary Amines ◽

Dimroth Rearrangement ◽

H Nmr ◽

New Synthesis ◽

C Nmr

New synthesis of pyrido[3,4-e]-1,3-thiazines consisting in reaction of 2,6-dimethyl-4-chloronicotinoyl isothiocyanate with primary or secondary amines, or with benzaldehyde phenylhydrazone, is described. High reactivity of the chlorine atom does not allow isolation of the corresponding thioureas, arising as intermediates, except in the case of the benzylamino derivative. Structure of the products was unequivocally confirmed by their spectral data (IR, UV, 1H NMR, 13C NMR and mass spectra). The synthesized derivatives do not undergo the Dimroth rearrangement.

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