Rhodium(II) catalyzed highly diastereoselective synthesis of conformationally restricted dispiro[1,3-dioxolane]bisoxindoles
作者:Sengodagounder Muthusamy、Rajagopal Ramkumar
DOI:10.1016/j.tet.2014.06.085
日期:2014.9
Synthesis of conformationally restricted dispiro- and bis-dispiro-1,3-dioxolanes via three-component reaction of diazoamides, ketoamides/diketones, and aromatic/heteroaromatic aldehydes in the presence of rhodium(II) acetate dimer catalyst at room temperature involving carbonyl ylides is demonstrated with diastereoselectivity. Synthesis of macrocyclic dispiro-1,3-dioxolanes via intramolecular carbonyl
An Investigation into the Cytotoxicity and Mode of Action of Some Novel <i>N</i>-Alkyl-Substituted Isatins
作者:Kara L. Vine、Julie M. Locke、Marie Ranson、Stephen G. Pyne、John B. Bremner
DOI:10.1021/jm0704189
日期:2007.10.1
studies indicated that the introduction of an aromatic ring with a one or three carbon atom linker at N1 enhanced the activity from that of the allyl, 2'-methoxyethyl, and 3'-methylbutyl N-substituted isatins. Furthermore, electron-withdrawing groups substituted at the meta or para position of the ring were favored over the orthoorientation. Of the 24 compounds screened, nine displayed sub-micromolar IC50
which could serve as valuable synthetic building blocks. This is also the first time that a ketone has been used as the electrophile and acrolein as the nucleophile in a highly enantioselective catalyticasymmetric MBH reaction. Hatakeyama's catalyst, β-isocupreidine (1), turned out to be a powerful catalyst for this transformation.
The asymmetric synthesis of the 3-allyl-3-hydroxyoxindole skeleton was accomplished in yields up to 99% via a metal-free and enantioselective allylation of isatins (90–96% ee) using BINOL derivatives as catalysts and an optimized allylboronate. This methodology was applied at a gram-scale to the synthesis of the natural product (R)-chimonamidine.
An efficient protocol has been developed for the aqueous-mediated synthesis of 3,3-di(indolyl)oxindole derivatives via the electrophilic substitution reaction of indoles with various isatins using sulfonic acid-functionalized mesoporous silica nanoparticles (SAMSNs) as a recoverable heterogeneous acid catalyst. This catalyst can be reused several times without significant loss of activity.