Dienamine Catalysis: Organocatalytic Asymmetric γ-Amination of α,β-Unsaturated Aldehydes
2006; American Chemical Society; Volume: 128; Issue: 39 Linguagem: Inglês
10.1021/ja064637f
ISSN1943-2984
AutoresSøren Bertelsen, Mauro Marigo, Sebastian Brandes, Peter Dinér, Karl Anker Jørgensen,
Tópico(s)Synthesis and Catalytic Reactions
ResumoA new concept in organocatalysis is presented, the direct asymmetric gamma-functionalization of alpha,beta-unsaturated aldehydes. We disclose that secondary amines can invert the usual reactivity of alpha,beta-unsaturated aldehydes, enabling a direct gamma-amination of the carbonyl compound using azodicarboxylates as the electrophilic nitrogen-source. The scope of the reaction is demonstrated for the enantioselective gamma-amination of different alpha,beta-unsaturated aldehydes, giving the products in moderate to good yields and with high enantioselectivities up to 93% ee. Experimental investigations and DFT calculations indicate that the reaction might proceed as a hetero-Diels-Alder cycloaddition reaction. Such a mechanism can explain the "unexpected" stereochemical outcome of the reaction.
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