Low temperature electrochemistry as a mechanistic probe for the partial reduction of heterocycles

Donohoe, Timothy J.; Johnson, Dale J.; Compton, Richard G.; Wadhawan, Jay D.

doi:10.1016/j.tet.2004.05.027

Cited by 11 publications

(9 citation statements)

References 16 publications

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“…After learning that aryl halides such as benzyl Iodide and 4-methoxybenzyl iodide react with disubstituted pyridines to give pyridinium salts our investigations started with formation of pyridinium salt from 4-methoxybenzyl bromide 16 rather than the iodide 11 earlier prepared by Donohoe [5,7]. Preparation of the 4-methoxybenzyl bromide 16 followed the procedure used by Donohoe.…”

Section: Resultsmentioning

confidence: 99%

“…Donohoe have also reported extensive work in preparation of mono-substituted and di-substituted pyridinium salts used in Birch reductions and Ammoniafree Birch reductions [2][3][4][5]. For example Donohoe have investigated preparation of N-Methyl pyridinium salt 4 using similar conditions used by Boesrma (Scheme II).The salts prepared by Donohoe were intended for ammonia-free Birch reductions which gave positive results giving N-methyl dihydropyridine 5.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis, Reactivity and Stability of Aryl Halide Protecting Groups towards Di-Substituted Pyridines

Brian

Musau

2018

Indones. J. Chem.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthesis, Reactivity and Stability of Aryl Halide Protecting Groups towards Di-Substituted Pyridines

Brian

Musau

2018

Indones. J. Chem.

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“…The aspects of low temperature electrochemistry did develop as cryoelectrochemistry [125]. Cryoelectrochemistry (at around −70 • C), however, has been limited to electrochemical analysis in nonpolar solvents [126][127][128] and has rarely been investigated for aqueous solutions and electrochemical synthesis. Studies have been limited to synthesis of insoluble products to as low as 10…”

Section: Discussionmentioning

confidence: 99%

Evolution of Principle and Practice of Electrodeposited Thin Film: A Review on Effect of Temperature and Sonication

Mallik

Ray

2011

International Journal of Electrochemistry

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This review discusses briefly the important aspects of thin films. The introduction of the article is a summary of evolution of thin films from surface engineering, their deposition methods, and important issues. The fundamental aspects of electrochemical deposition with special emphasis on the effect of temperature on the phase formation have been reviewed briefly. The field of sonoelectrochemistry has been discussed in the paper . The literature regarding the effects of temperature and sonication on the structure and morphology of the deposits and nucleation mechanisms, residual stress, and mechanical properties has also been covered briefly.

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“…It was proposed that under the Birch reduction conditions, pyrrole 1 is electron‐deficient enough to accept two electrons resulting in formation of a, relatively, stable dianion which is not sufficiently basic enough to deprotonate ammonia. Formation of the dianion intermediate has been verified using electrochemical methods, which show transfer of two electrons in tetrahydrofuran (THF) at −78°C 6. Addition of an electrophile then causes subsequent alkylation at both C‐2 and C‐5 as described.…”

Section: Introductionmentioning

confidence: 91%

Partial reduction of pyrroles: application to natural product synthesis

Donohoe

Thomas

2007

The Chemical Record

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The partial reduction of N-Boc pyrroles has been explored giving stereoselective routes to disubstituted pyrrolines in good yields and with excellent diastereoselectivities. A novel methodology has been developed to carry out reductive aldol reactions on 2-substituted N-Boc pyrroles; use of aldehydes under reductive aldol conditions gave the anti aldol product in good selectivity. This chemistry was used as the key transformation in a synthesis of omuralide, which was achieved in 13 steps and 14% overall yield. We also report a methodology for selectively forming either cis or trans 2,5-disubstituted pyrrolines via a partial reduction of an electron-deficient N-Boc pyrrole. The trans pyrroline formed using this route was utilized in the syntheses of the polyhydroxylated pyrrolizidine natural products hyacinthacine A1 and 1-epiaustraline. Further investigation has led to the development of routes to enantiopure substituted pyrroline compounds. This has been achieved via a chiral protonation approach using easily accessible chiral acids, such as ephedrine and oxazolidinones, to quench enolates formed during the partial reduction process. Alternatively, enzymatic desymmetrization of symmetrical diol compounds formed from the partial reduction products of substituted pyrroles is also reported. This leads to formation of both enantiomers of 2,2- and 2,5-disubstituted N-Boc pyrrolines in excellent ee and yields.

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Low temperature electrochemistry as a mechanistic probe for the partial reduction of heterocycles

Cited by 11 publications

References 16 publications

Synthesis, Reactivity and Stability of Aryl Halide Protecting Groups towards Di-Substituted Pyridines

Synthesis, Reactivity and Stability of Aryl Halide Protecting Groups towards Di-Substituted Pyridines

Evolution of Principle and Practice of Electrodeposited Thin Film: A Review on Effect of Temperature and Sonication

Partial reduction of pyrroles: application to natural product synthesis

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