Selective Reductions. XI. The Reaction of Sodium Borohydride with Alkyl Halides under Solvolytic Conditions. Borohydride as a Convenient Trap for Carbonium Ions<sup>1,2</sup>

Bell, Harold M.; Brown, Herbert C.

doi:10.1021/ja00959a028

Cited by 67 publications

(12 citation statements)

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“…Unlike LiAlH 4 , sodium boron hydride (NaBH 4 ) is relatively stable in water and many mixed aqueous systems suitable for solvolytic generation of carbonium cations. Secondary and tertiary chlorohydrocarbons are reduced under these conditions with a high yield of hydrocarbons [161]. The basic side processes are dehydrochlorination and pyrolysis.…”

Section: Reduction Of Organochlorine Compounds With Metal Hydrides Anmentioning

confidence: 99%

Theoretical and Applied Aspects of Hydrodechlorination Processes—Catalysts and Technologies

Flid¹,

Kartashov²,

Treger³

2020

Catalysts

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The commercial implementation of hydrodechlorination processes will be an essential step in resolving the problem of environmentally sound organochlorine wastes processing. By now, there is a number of fundamental, applied, and process elaborations of such processes, in which chlorine is almost completely removed from wastes. The review article contains a significant number of results including basic regularities of thermal hydrodechlorination, comprehensive and selective catalytic hydrodechlorination. It discusses thermodynamics, kinetics, and catalysts of gas and liquid phase processes. Considerable attention is paid to hydrodechlorination of vinyl chloride production wastes and utilization of tetrachloromethane, which is the ozone-depleting substance. It also discusses hydrodechlorination of mono-and (poly)chlorobenzenes. The important examples of liquid phase data include hydrogenation using complex hydrides of elements. It also includes several flow sheets of hydrodechlorination processes.Various methods for C-Cl bonds reduction in non-cyclic organochlorine compounds can be divided into the following groups:Catalysts 2020, 10, 216 3 of 52 one should note the reviews [4,10] published in the 1990s. It is noted that catalytic methods are more widely used for hydrodechlorination. Electrochemical ReductionElectrochemical reduction is a complex process in which the speed and direction of reactions depend on many factors. It is characterized by the following features. Two electrons are spent for breaking the C-Cl bond; the half-wave potential in most cases does not depend on the pH of the medium; in general, the electrode reaction is irreversible [1]. There is an approximate linear relationship between the half-wave potential of the reactionsIn [12], a scheme was proposed describing the mechanism of electrochemical reduction of the C-Cl bondRClHowever, there is another point of view, according to which there is a simultaneous transfer of a pair of electrons, similar to that for nucleophilic substitution reactions [1].Electrochemical reduction is carried out on cathodes of copper, zinc, amalgamated zinc, palladium, cadmium, mercury, and lead [13]. The cathodic dechlorination proceeds in an alkaline environment more efficiently than in an acidic one; however, in most cases, acidic electrolytes are used to avoid such side reactions as saponification [13,14]. The recovery is usually carried out in inert solvents, in particular in alcohols. In [13], the influence of the reduction conditions-the cathode material, current density, the nature of electrolyte and solvent, the concentration of the reducible substance, and temperature-on the course of the reaction is described.The recovery of monochlorohydrocarbons is difficult and results mainly in the replacement of chlorine by hydrogen in accordance with the overall equationIn some cases, dimeric compounds (R-R) are formed according to the schemeThe recovery of vinyl chlorine is difficult, and that of the allyl one is facilitated in comparison with chlorine in saturated com...

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Section: Reduction Of Organochlorine Compounds With Metal Hydrides Anmentioning

confidence: 99%

Theoretical and Applied Aspects of Hydrodechlorination Processes—Catalysts and Technologies

Flid¹,

Kartashov²,

Treger³

2020

Catalysts

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“…The phenomenon of hydrogen-deuterium exchange at the 8-C ring position of purines was first detected using nuclear magnetic resonance techniques1•2 and has (1) . P. Schweizer, S. I. Chan, G. K. Helmkamp, and P. O. P. Ts'o, J. Amer.…”

Section: Detection Of Hydrogen-deuterium Exchange Inmentioning

confidence: 99%

Dehalogenations with sodium borohydride. Evidence for a free radical reaction

Groves¹,

Ma²

1974

J. Am. Chem. Soc.

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Reduction of alkyl and aryl halides with sodium borohydride is well known and has been reported, variously, to proceed via an SnI process,1 an Sn2 process, or nucleophilic attack on halogen2 depending on the structure of the halide. Only recently has evidence appeared suggesting dehalogenation by a free radical path.3 In the course of our recent examination of the reaction of -bromocyclopropyl trifluoroacetates4 with hydride reagents to afford cyclopropanols,6 it became apparent that gem-dibromocyclopropanes are appreciably reactive toward sodium borohydride as well, affording high yields of the corresponding mono-

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“…Hydroboration of the olefin with disiamylborane according to the procedure of Brown21 afforded two products as indicated by VPC analysis on column C (175 °C). The major, first eluted component was identified as exo-l,4,4-trimethylbicyclo-[3.2.1]octan-6-ol (29): mp 26-29 °C; IR 3605 (w), 3550-3100 (br), 2940 (s), 2907 (5), 2852 (m), 1452 (m), 1386 (m), 1368 (m), 1088 (m), 1040 (m), 985 (w), 900 cm"1 (w); NMR (60 MHz) 4.12 (dd, y,3, 7 Hz, 1 ), 2.00 (s, 1 ) 1.93-1.06 (m, 9 ), 1.05 (s, 3 ), 0.95 (s, 3 ), 0.90 (s, 3 H); mass spectrum m/e 168.1514 (M+, caled for C11H20O, 168.1513). The second component was identified as exo-1,4,4-trimethylbicyclo[3.2.1 ]octan-7-ol (30): IR 3610 (w), 2955 (s), 2915 (s), 2860 (m), 1460 (m), 1377 (w), 1360 (w), 1045 cm"1 (m); NMR (60 MHz) 3.56 (dd, J = 3, 7 Hz, 1 ), 2.42-1.05 (m, 10 H), 0.93 (s, 6 ), 0.82 (s, 3 H); mass spectrum m/e 168.1500.…”

Section: Discussionmentioning

confidence: 99%

Photochemistry of bicyclo[3.2.1]octan-6-ones. Stereoselectivity of hydrogen transfer in disproportionation of biradical intermediates

Agosta¹,

Wolff²

1977

J. Am. Chem. Soc.

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Selective Reductions. XI. The Reaction of Sodium Borohydride with Alkyl Halides under Solvolytic Conditions. Borohydride as a Convenient Trap for Carbonium Ions^1,2

Cited by 67 publications

References 0 publications

Theoretical and Applied Aspects of Hydrodechlorination Processes—Catalysts and Technologies

Theoretical and Applied Aspects of Hydrodechlorination Processes—Catalysts and Technologies

Dehalogenations with sodium borohydride. Evidence for a free radical reaction

Photochemistry of bicyclo[3.2.1]octan-6-ones. Stereoselectivity of hydrogen transfer in disproportionation of biradical intermediates

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Selective Reductions. XI. The Reaction of Sodium Borohydride with Alkyl Halides under Solvolytic Conditions. Borohydride as a Convenient Trap for Carbonium Ions1,2

Cited by 67 publications

References 0 publications

Theoretical and Applied Aspects of Hydrodechlorination Processes—Catalysts and Technologies

Theoretical and Applied Aspects of Hydrodechlorination Processes—Catalysts and Technologies

Dehalogenations with sodium borohydride. Evidence for a free radical reaction

Photochemistry of bicyclo[3.2.1]octan-6-ones. Stereoselectivity of hydrogen transfer in disproportionation of biradical intermediates

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Selective Reductions. XI. The Reaction of Sodium Borohydride with Alkyl Halides under Solvolytic Conditions. Borohydride as a Convenient Trap for Carbonium Ions^1,2