3946-09-6Relevant articles and documents
Stereostructure of komodoquinone A, a neuritogenic anthracycline, from marine Streptomyces sp. KS3
Itoh, Takuya,Kinoshita, Masahiro,Wei, Hong,Kobayashi, Motomasa
, p. 1402 - 1404 (2003)
The absolute stereostructure of komodoquinone A (1), a neuritogenic anthracycline, which was isolated from a cultured marine Streptomyces sp. KS3, has been determined on the basis of chemical derivatization. Komodoquinone A (1) induces neuronal cell differentiation in the neuroblastoma cell line, Neuro 2A and arrests the cell cycle at the G1 phase. The effect of a solid-state medium on the production of 1 and its aglycone, komodoquinone B (2), was examined.
Biocatalytic Construction of Quaternary Centers by Aldol Addition of 3,3-Disubstituted 2-Oxoacid Derivatives to Aldehydes
Marín-Valls, Roser,Hernández, Karel,Bolte, Michael,Parella, Teodor,Joglar, Jesús,Bujons, Jordi,Clapés, Pere
supporting information, p. 19754 - 19762 (2020/12/01)
The congested nature of quaternary carbons hinders their preparation, most notably when stereocontrol is required. Here we report a biocatalytic method for the creation of quaternary carbon centers with broad substrate scope, leading to different compound classes bearing this structural feature. The key step comprises the aldol addition of 3,3-disubstituted 2-oxoacids to aldehydes catalyzed by metal dependent 3-methyl-2-oxobutanoate hydroxymethyltransferase from E. coli (KPHMT) and variants thereof. The 3,3,3-trisubstituted 2-oxoacids thus produced were converted into 2-oxolactones and 3-hydroxy acids and directly to ulosonic acid derivatives, all bearing gem-dialkyl, gem-cycloalkyl, and spirocyclic quaternary centers. In addition, some of these reactions use a single enantiomer from racemic nucleophiles to afford stereopure quaternary carbons. The notable substrate tolerance and stereocontrol of these enzymes are indicative of their potential for the synthesis of structurally intricate molecules.
The first practical approach to optically pure cyclopropanes derived from trans γ-hydroxy enones
Palmer, Francine N.,Taylor, Dennis K.
, p. 1323 - 1325 (2007/10/03)
The optically pure cyclopropanes derived from trans γ-hydroxy enones were discussed. The trans γ-hydroxy enones were found to be prepared from reaction of stabilized ketoylides on optically pure α hydroxy aldehydes. The analysis showed that the use of light and a triplet sensitizer lead to a dramatic increase in reaction rate and isolated yield.