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Iron-catalysed, general and operationally simple formal hydrogenation using Fe(OTf)3 and NaBH4.

MacNair AJ, Tran MM, Nelson JE, Sloan GU, Ironmonger A, Thomas SP - Org. Biomol. Chem. (2014)

Bottom Line: An operationally simple and environmentally benign formal hydrogenation protocol has been developed using highly abundant iron(iii) salts and an inexpensive, bench stable, stoichiometric reductant, NaBH4, in ethanol, under ambient conditions.This reaction has been applied to the reduction of terminal alkenes (22 examples, up to 95% yield) and nitro-groups (26 examples, up to 95% yield).Deuterium labelling studies indicate that this reaction proceeds via an ionic rather than radical mechanism.

View Article: PubMed Central - PubMed

Affiliation: School of Chemistry, University of Edinburgh, Joseph Black Building, West Mains Road, Edinburgh EH9 3JJ, UK. stephen.thomas@ed.ac.uk.

ABSTRACT
An operationally simple and environmentally benign formal hydrogenation protocol has been developed using highly abundant iron(iii) salts and an inexpensive, bench stable, stoichiometric reductant, NaBH4, in ethanol, under ambient conditions. This reaction has been applied to the reduction of terminal alkenes (22 examples, up to 95% yield) and nitro-groups (26 examples, up to 95% yield). Deuterium labelling studies indicate that this reaction proceeds via an ionic rather than radical mechanism.

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Formation of halogenated side products, X = Cl/Br.
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sch2: Formation of halogenated side products, X = Cl/Br.

Mentions: Iron(iii) chloride, bromide and triflate supported the reduction (entries 1–4); however when stoichiometric FeCl3 or FeBr3 were used, (3-chlorobutyl)benzene 4a and (3-bromobutyl)benzene 4b were obtained as side-products respectively. This was presumably as a result of radical formation, followed by halide abstraction from the iron salt (Scheme 2).20


Iron-catalysed, general and operationally simple formal hydrogenation using Fe(OTf)3 and NaBH4.

MacNair AJ, Tran MM, Nelson JE, Sloan GU, Ironmonger A, Thomas SP - Org. Biomol. Chem. (2014)

Formation of halogenated side products, X = Cl/Br.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4295815&req=5

sch2: Formation of halogenated side products, X = Cl/Br.
Mentions: Iron(iii) chloride, bromide and triflate supported the reduction (entries 1–4); however when stoichiometric FeCl3 or FeBr3 were used, (3-chlorobutyl)benzene 4a and (3-bromobutyl)benzene 4b were obtained as side-products respectively. This was presumably as a result of radical formation, followed by halide abstraction from the iron salt (Scheme 2).20

Bottom Line: An operationally simple and environmentally benign formal hydrogenation protocol has been developed using highly abundant iron(iii) salts and an inexpensive, bench stable, stoichiometric reductant, NaBH4, in ethanol, under ambient conditions.This reaction has been applied to the reduction of terminal alkenes (22 examples, up to 95% yield) and nitro-groups (26 examples, up to 95% yield).Deuterium labelling studies indicate that this reaction proceeds via an ionic rather than radical mechanism.

View Article: PubMed Central - PubMed

Affiliation: School of Chemistry, University of Edinburgh, Joseph Black Building, West Mains Road, Edinburgh EH9 3JJ, UK. stephen.thomas@ed.ac.uk.

ABSTRACT
An operationally simple and environmentally benign formal hydrogenation protocol has been developed using highly abundant iron(iii) salts and an inexpensive, bench stable, stoichiometric reductant, NaBH4, in ethanol, under ambient conditions. This reaction has been applied to the reduction of terminal alkenes (22 examples, up to 95% yield) and nitro-groups (26 examples, up to 95% yield). Deuterium labelling studies indicate that this reaction proceeds via an ionic rather than radical mechanism.

Show MeSH