Metallation of N-Substituted β-Lactams. A Method for the Introduction of 3-Substituents into β-Lactams

1972 ◽  
Vol 50 (19) ◽  
pp. 3196-3201 ◽  
Author(s):  
T. Durst ◽  
M. J. LeBelle
Keyword(s):  
Good Yield ◽  
Alkyl Halides ◽  
Lithium Diisopropylamide

N-Alkyl and N-aryl β-lactams yield lithio carbanions upon reaction with lithium diisopropylamide in tetrahydrofuran at −78°. These lithio salts react with a variety of electrophiles (e.g. ketones, esters, reactive alkyl halides) to give the 3-substituted derivatives in fair to good yield. The procedure is useful for the preparation of rather complex 3-substituted β-lactams from readily available simple derivatives.

The Chemistry of 5-Oxodihydroisoxazoles. X. Butyllithium and Lithium Diisopropylamide Promoted Rearrangements of 3-Unsubstituted Isoxazol-5(2H)-ones

1994 ◽  
Vol 47 (9) ◽  
pp. 1673 ◽  
Author(s):  
RH Prager ◽  
P Razzino
Keyword(s):  
Reaction Pathway ◽  
Alkyl Halides ◽  
Lithium Diisopropylamide ◽  
Methyl Phenyl

The reaction pathway of 3-unsubstituted isoxazol-5(2H)-ones with bases, proposed by Woodman1-3 to proceed via four intermediates to azetidine-2,4-diones, has been confirmed by the isolation of products unequivocally derived from each of the intermediates. Isoxazol-5(2H)-ones substituted on nitrogen by methyl, phenyl, quinolin-2-yl and vinyl groups have been studied. The azetidine-2,4-diones have only been isolated when the intermediate enolate has been alkylated , but only reactive alkyl halides lead to useful syntheses.

Organophosphorus compounds. V. Dialkyl alkylphosphonates from alkyl halides and sodium dialkyl phosphonates in liquid ammonia

1965 ◽  
Vol 18 (2) ◽  
pp. 163 ◽  
Author(s):  
A Meisters ◽  
JM Swan
Keyword(s):  
Carbon Tetrachloride ◽  
Good Yield ◽  
Benzyl Chloride ◽  
Liquid Ammonia ◽  
Organophosphorus Compounds ◽  
Alkyl Halides ◽  
Ethyl Bromide ◽  
Equivalent Quantity ◽  
Dialkyl Phosphonates

Liquid ammonia is a useful solvent for the reaction of various alkyl halides with sodium dialkyl phosphonates. In this medium ethyl bromide, amyl bromide, octyl bromide, ally1 chloride, and benzyl chloride give the corresponding dialkyl alkylphosphonates in good yield. In other cases, alternative products are formed. Thus sodium diethyl phosphonate reacts with carbon tetrachloride or chloroform in liquid ammonia to give diethyl phosphoramidate; dibromomethane gives diethyl methylphosphonate and an equivalent quantity of diethyl phosphoramidate. p-Nitrobenzyl bromide gives mainly 1,2-di(p-nitrophenyl)ethane, 1-bromooct-1-yne is reduced to oct-1-yne, and 3-bromoprop-1-yne gives mainly propyne together with some diethyl prop-l- ynylphosphonate.

scholarly journals Substitution α to the Nitrogen in Dibenzylamine via Carbanion Intermediates

1973 ◽  
Vol 51 (7) ◽  
pp. 1109-1115 ◽  
Author(s):  
Robert R. Fraser ◽  
Guy Boussard ◽  
I. Dan Postescu ◽  
Josephine J. Whiting; ◽  
Yuk Y. Wigfield
Keyword(s):  
Nitrogen Atom ◽  
Carbonyl Compounds ◽  
Alkyl Halides ◽  
Lithium Diisopropylamide ◽  
Derivatives Of

A method has been developed for introducing a variety of substituents into the position α to the nitrogen atom of dibenzylamine. Treatment of either the nitroso or the benzoyl derivative of dibenzylamine with lithium diisopropylamide generates a carbanion which reacts with alkyl halides or carbonyl compounds producing α-substitution products in yields of 66–99%. The method also gives good yields of derivatives of N-phenyl-N′-nitroso-piperazine. Attempts to form the carbanion of N-benzoylpiperidine failed.

Vitamin B12-based elimination of alkyl halides

2020 ◽  
Author(s):  
Julian West ◽  
Alexandros S Pollatos ◽  
Radha Bam
Keyword(s):  
Vitamin B12 ◽  
Alkyl Halides

Fe-Catalyzed Conjunctive Cross-Couplings of Unactivated Alkenes with Grignard Reagents

2020 ◽  
Author(s):  
Lei Liu ◽  
Wes Lee ◽  
Cassandra R. Youshaw ◽  
Mingbin Yuan ◽  
Michael B. Geherty ◽  
...  
Keyword(s):  
Functional Groups ◽  
Cross Coupling ◽  
Alkyl Halides ◽  
Grignard Reagents ◽  
Turnover Frequency ◽  
Diverse Range ◽  
Cascade Cyclization ◽  
Radical Cascade

The first iron-catalyzed three-component cross-coupling of unactivated olefins with alkyl halides and Grignard reagents is reported. The reaction operates under fast turnover frequency and tolerates a diverse range of sp2-hybridized nucleophiles, alkyl halides, and unactivated olefins bearing diverse functional groups to yield the desired 1,2-alkylarylated products with high regiocontrol. Further, we demonstrate that this protocol is amenable for the synthesis of new (hetero)carbocycles including tetrahydrofurans and pyrrolidines via a three-component radical cascade cyclization/arylation that forges three new C-C bonds.

Nickel-Catalyzed Inter- and Intramolecular Carbon-Sulfur Bond Metathesis by Reversible Arylation

2019 ◽  
Author(s):  
Tristan Delcaillau ◽  
Alessandro Bismuto ◽  
Zhong Lian ◽  
Bill Morandi
Keyword(s):  
Good Yield ◽  
Functional Group ◽  
Product Formation ◽  
Single Bond ◽  
Ring Closing Metathesis ◽  
Catalytic Systems ◽  
Metathesis Reactions ◽  
New Applications ◽  
Further Development ◽  
Sulfur Bond

A nickel-catalyzed carbon-sulfur bond metathesis has been developed to access high-value thioethers. 1,2-bis(dicyclohexylphosphino)ethane (dcype) is essential to promote this highly functional group tolerant reaction. Further, synthetically challenging macrocycles could be obtained in good yield in an unusual example of ring-closing metathesis which does not involve alkene bonds. In-depth organometallic studies support a reversible Ni(0)-Ni(II) pathway to product formation. Overall, this work does not only disclose a more sustainable and more functional group tolerant alternative to previous catalytic systems based on Pd, but also presents new applications and mechanistic information which are highly relevant to the further development and application of unusual single bond metathesis reactions.

Design and Development of Fe-Catalyzed Intra- and Intermolecular Carbofunctionalization of Vinyl Cyclopropanes

2019 ◽  
Author(s):  
Lei Liu ◽  
Wes Lee ◽  
Mingbin Yuan ◽  
Chris Acha ◽  
Michael B. Geherty ◽  
...  
Keyword(s):  
Bond Formation ◽  
Cross Coupling ◽  
Alkyl Halides ◽  
Grignard Reagents ◽  
Mechanistic Studies ◽  
Radical Intermediates ◽  
Design And Implementation ◽  
Solvent Cage ◽  
Radical Cascade ◽  
Radical Processes

Design and implementation of the first (asymmetric) Fe-catalyzed intra- and intermolecular difunctionalization of vinyl cyclopropanes (VCPs) with alkyl halides and aryl Grignard reagents has been realized via a mechanistically driven approach. Mechanistic studies support the diffusion of the alkyl radical intermediates out of the solvent cage to participate in an intra- or -intermolecular radical cascade with the VCP followed by re-entering the Fe radical cross-coupling cycle to undergo selective C(sp2)-C(sp3) bond formation. Overall, we provide new design principles for Fe-mediated radical processes and underscore the potential of using combined computations and experiments to accelerate the development of challenging transformations.

Nickel and Cobalt-Catalyzed Coupling of Alkyl Halides with Alkenes via Heck Reactions and Radical Conjugate Addition

2013 ◽  
Vol 13 (6) ◽  
pp. 802-813 ◽  
Author(s):  
Qun Qian ◽  
Zhenhua Zang ◽  
Yang Chen ◽  
Weiqi Tong ◽  
Hegui Gong
Keyword(s):  
Conjugate Addition ◽  
Alkyl Halides ◽  
Heck Reactions

Efficient CDI/CH3SO3H -Catalyzed, Microwave-Assisted Synthesis of 2-Substituted Benzothiazoles

2018 ◽  
Vol 16 (1) ◽  
pp. 34-39
Author(s):  
Yao-Wei Li ◽  
Pei-Ming Zhang ◽  
Rui Li ◽  
Yan Bai ◽  
Yu Yu ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Carboxylic Acids ◽  
1H Nmr ◽  
Good Yield ◽  
Microwave Assisted Synthesis ◽  
Synthetic Method ◽  
Benzothiazole Derivatives ◽  
Microwave Assisted ◽  
Highly Effective

CDI combined with CH3SO3H was found to be highly effective for the cyclization of 2-aminothiophenol derivatives with carboxylic acids under MW condition. Fourteen benzothiazole derivatives were synthesized in good yield and their structures were characterized by 1H-NMR, 13CNMR, IR and mass spectrometry. This simple, rapid synthetic method is believed to provide a useful process for the synthesis of 2-substituted benzothiazole compounds.

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