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A Novel NO 2 /OH Exchange in α‐Nitro Ketones: A mechanistic investigation
Author(s) -
Yurdakul Ayçil,
Gurtner Christian,
Jung ElenaSilvia,
LorenziRiatsch Annalaura,
Linden Anthony,
Guggisberg Armin,
Bienz Stefan,
Hesse Manfred
Publication year - 1998
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19980810547
Subject(s) - chemistry , nitro , deprotonation , nucleophile , stereocenter , medicinal chemistry , solvent , reaction mechanism , aqueous solution , stereochemistry , organic chemistry , catalysis , enantioselective synthesis , ion , alkyl
The reaction of α‐nitro ketones to the corresponding α‐hydroxy ketones under basic aqueous conditions, a novel transformation, was studied. The investigation revealed that the reaction is only possible with α‐nitro ketones that are CH‐acidic in the α′‐position and readily deprotonated under the reaction conditions. The NO 2 /OH exchange was established to proceed with retention of configuration at the stereogenic center, and labeling experiments have shown that the OH O‐atom originates, to a great extent, from the solvent. In particular, the stereochemical course of the reaction and the incorporation of external nucleophiles led us to propose a mechanism that involves neighboring‐group participation. The product formation is explained by a double S N 2 reaction, which proceeds via a Favorskii ‐like cyclopropanone intermediate.