Researchers claim to have developed a new protecting group that can shield amine groups during organic reactions and then be removed under extremely mild conditions.
Protecting groups are heavily used in multi-step organic synthesis to mask particularly reactive functional groups. Paul Knochel and Nina Gommermann of the Ludwig-Maximilians University in Munich have designed a new protecting group for amines which is stable under both acidic and basic reaction conditions but mildly and selectively removable using palladium.
It was tested in the one-pot three-component reaction of the protected amine with an aldehyde and an alkyne. The bulky protecting group, in combination with a chiral catalyst, ensured the reaction proceeded with high stereochemical selectivity. Crucially, the protecting group could then be removed catalytically, using palladium at room temperature, without destroying the delicate product.
Knochel is now looking to synthesise other sensitive amines using this strategy.
James Mitchell Crow
N Gommermann and P Knochel, Chem. Commun., 2005, 4175 (DOI: 10.1039/b507810e)