AuBr3-catalyzed thiooxime-to-carbonyl conversion: from chiral aliphatic nitro compounds to ketones without racemization.
A new variant of the NO(2)-to-CO transformation (the Nef reaction) that occurs at room temperature under neutral conditions is uncovered. After the conversion of secondary nitroalkanes to phenylsulfenylketimines, these thiooximes are hydrolyzed quantitatively in situ, in THF-H(2)O at pH 7, by addition of AuBr(3) (but not with other MX(n)!). Adducts arising from asymmetric nitro-Michael and nitro-aldol reactions afford 1,4-diketones and alpha-alkoxy ketones, respectively, with full retention of the configuration of the stereocenters alpha to the CHNO(2)/C=N-SPh/C=O groups.
Burés
Jordi
J
Departament de Química Orgànica, Facultat de Química, Universitat de Barcelona, Diagonal 647, 08028 Barcelona, Catalonia, Spain.
Isart
Carles
C
Vilarrasa
Jaume
J