نتایج جستجو برای: oxindole
تعداد نتایج: 442 فیلتر نتایج به سال:
An organocatalytic conjugate addition of prochiral 3-fluorinated oxindoles to vinyl sulfones was described for the first time. In the presence of bifunctional tertiary amine-thiourea catalysts, 3-fluoro-3-substituted oxindole adducts were obtained in excellent yields and with high enantiomeric excesses.
The first organocatalytic Michael-cyclization cascade reaction between isothiocyanato oxindoles and unsaturated pyrazolones has been developed. The multicyclic spiro[oxindole/thiobutyrolactam/pyrazolone] core structures containing three contiguous stereogenic centers, including two spiro quaternary centers, were prepared with excellent diastereo- (up to >20 : 1) and enantioselectivities (up to ...
An N-heterocyclic carbene (NHC)-catalyzed annulation reaction of isatin N-Boc ketimines and enals is developed for the synthesis of spirocyclic oxindole-γ-lactams bearing one quaternary chiral center in good yields and excellent stereoselectivities (up to >20:1 dr and 99% ee).
A new strategy for the construction of optically active 5'-CF3 spiro[pyrrolidin-3,2'-oxindole] was described. A series of unprecedented 1,3-dipoles were obtained by condensation of CF3CH2NH2 with isatins. The 1,3-dipolar cycloaddition reactions of these ketimines with enals gave the products bearing four contiguous stereogenic centers in excellent yields, diastereoselectivities and enantioselec...
The paper presents an application of the asymmetry approach to spirooxindoles via Brevicolline, Cinchonidine or Cinchonine catalyzed one-pot multicomponent synthesis. Brevicolline, in comparison with Cinchonidine or Cinchonine, catalyzes the reaction of isatins, acetylacetone/ethyl 3-oxobutanoate and malononitrile, with the formation of spiro[oxindole-3,4'-4'H-pirane] derivatives in an opticall...
In the title compound, C(21)H(20)FN(3)O(5), the the pyrrolidine ring makes dihedral angles of 84.91 (6) and 62.38 (7)° with the oxindole unit and the fluoro-phenyl ring, respectively. The pyrrolidine ring assumes an envelope conformation with the spiro C atom as the flap. The crystal packing features weak N-H⋯N and C-H⋯O hydrogen bonds.
The important cereal crops of maize, rye, and wheat constitutively produce precursors to 2-benzoxazolinone, a phytochemical having antifungal effects towards many Fusarium species. However, verticillioides can tolerate 2-benzoxazolinone by converting it into non-toxic metabolites through the synergism two previously identified gene clusters, FDB1 FDB2 . Inspired induction these clusters upon ex...
rearrangement were elucidated and we assumed that a total synthesis of 1would be a straightforwardmatter. As described below, we were indeed able to accomplish the inaugural total synthesis of phalarine using the rearrangement strategy, although significant obstacles had to be overcome. For a total synthesis of phalarine, it would be best if the rearrangement could be conducted on an advanced-s...
A copper-catalyzed asymmetric α-hydrophosphonylation of isatins with a novel fluorous bis(oxazoline) as a ligand is presented. The corresponding chiral α(1)-oxindole-α-hydroxyphosphonates were obtained in 30-91% yield with enantioselectivities up to 92%. The fluorous ligand can be easily recovered and reused at least 3 times without a significant loss in its activity.
A simple and practical copper-catalyzed approach to oxindole derivatives by copper-catalyzed bis-arylation of N-alkyl-N-phenylacrylamides with diaryliodonium triflates has been developed under mild conditions, and the method is of tolerance towards some functional groups in the substrates.
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