Limits...
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.

Show MeSH

Related in: MedlinePlus

Deuterium labelling studies for the investigation of the mechanism of iron-catalysed, NaBH4 mediated, alkene reduction.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4295815&req=5

sch3: Deuterium labelling studies for the investigation of the mechanism of iron-catalysed, NaBH4 mediated, alkene reduction.

Mentions: Reduction of 4-phenyl-1-butene 1a using NaBD4 and d1-ethanol gave exclusively the dideuterated alkane d2-2a (Scheme 3a). In line with previous reports of deuterium exchange between NaBD4 and alcoholic solvents,28 performing the reduction with NaBD4 and ethanol gave a mixture of deuterated and non-deuterated alkanes (Scheme 3b). In both cases deuterium was incorporated in both C3 and C4 positions of the alkane. In order to probe the existence of a radial intermediate, d5-EtOH was used as the reaction solvent to probe radical abstraction from the CD2OH position, however, no deuterium incorporation was observed (Scheme 3c). This suggests an ionic, rather than radical mechanism.


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)

Deuterium labelling studies for the investigation of the mechanism of iron-catalysed, NaBH4 mediated, alkene reduction.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

sch3: Deuterium labelling studies for the investigation of the mechanism of iron-catalysed, NaBH4 mediated, alkene reduction.
Mentions: Reduction of 4-phenyl-1-butene 1a using NaBD4 and d1-ethanol gave exclusively the dideuterated alkane d2-2a (Scheme 3a). In line with previous reports of deuterium exchange between NaBD4 and alcoholic solvents,28 performing the reduction with NaBD4 and ethanol gave a mixture of deuterated and non-deuterated alkanes (Scheme 3b). In both cases deuterium was incorporated in both C3 and C4 positions of the alkane. In order to probe the existence of a radial intermediate, d5-EtOH was used as the reaction solvent to probe radical abstraction from the CD2OH position, however, no deuterium incorporation was observed (Scheme 3c). This suggests an ionic, rather than radical mechanism.

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
Related in: MedlinePlus