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Direct Asymmetric α‐Sulfamidation of α‐Branched Aldehydes: A Novel Approach to Enamine Catalysis
Author(s) -
Vogt Henning,
Baumann Thomas,
Nieger Martin,
Bräse Stefan
Publication year - 2006
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200600587
Subject(s) - chemistry , enamine , aldehyde , sodium azide , catalysis , azide , cycloaddition , sulfonyl , organic chemistry , combinatorial chemistry , alkyl
Proline‐catalysed reactions between α‐branched aldehydes and sulfonyl azides provide scalemic configurationally stabilised α‐sulfamidated products with ee values of up to 86 %. The reactions can also be carried out in a one‐pot fashion, with catalyst, aldehyde, sulfonyl chloride and sodium azide. The proposed mechanism differs fundamentally from the mechanistic model usually ascribed to enamine catalysis, containing as a key step the diastereoselective cycloaddition of the azide to an enamine formed in situ. The products obtained in the reaction can be converted into the corresponding unnatural amino acids in two additional steps.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)