Exercising Regiocontrol in Palladium-Catalyzed Asymmetric Prenylations and Geranylation: Unifying Strategy toward Flustramines A and B
摘要:
Pd-catalyzed asymmetric prenylation of oxindoles to afford selectively either the prenyl or reverse-prenyl product has been demonstrated. Control of the regioselectivity in this transformation is governed by the choice of ligand, solvent, and halide additive. The resulting prenylated and reverse-prenylated products were transformed into ent-flustramides and ent-flustramines A and B. Additionally, control of the regio- and diastereoselectivity was obtained using pi-geranylpalladium complexes.
materials toward more complex oxindole-based structures. These molecules can be prepared by the reduction of a 3-ylidene oxindole precursor by classical metal-catalysed chemical reductions of the olefin. In this work we present a biocatalytic approach for the reduction of oxindole-based olefins using baker'syeast. All the substrates were efficiently reduced in high yields. When an α,β-unsaturated ketone
作者:Ekaterina V. Zaryanova、Nataly A. Lozinskaya、Olga V. Beznos、Maria S. Volkova、Nataly B. Chesnokova、Nikolay S. Zefirov
DOI:10.1016/j.bmcl.2017.06.065
日期:2017.8
the prolonged effect (more than 6 h) of the lead-compound. This effect in combination with high IOP reducing effect (41 ± 6%) in low concentrations of the active compound (0.1 wt%) and with high water solubility represents a great potential of low-cost oxindole derivatives as potent antiglaucoma agents.
Enantioselectivity-Switchable Organocatalytic [4 + 2]-Annulation to Access the Spirooxindole–Norcamphor Scaffold
作者:Jing Wang、Xian-Zhou Zheng、Jun-An Xiao、Kai Chen、Hao-Yue Xiang、Xiao-Qing Chen、Hua Yang
DOI:10.1021/acs.orglett.0c04164
日期:2021.2.5
An organocatalyzed enantiodivergent synthesis of a multifunctionalized spirooxindole–norcamphorscaffold via a [4 + 2]-annulation between cyclicα, β-unsaturated ketone and methylene indolinones has been established. The presence of CaCl2 in DMF could reverse the enantioselectivity to facilely deliver the enantiomers of the corresponding spirooxindoles. Both enantiomers of the corresponding spirooxindoles
Pd(0)-Catalyzed Chemoselective Deacylative Alkylations (DaA) of <i>N</i>-Acyl 2-Oxindoles: Total Syntheses of Pyrrolidino[2,3-<i>b</i>]indoline Alkaloids, (±)-Deoxyeseroline, and (±)-Esermethole
作者:Nivesh Kumar、Vipin R. Gavit、Arindam Maity、Alakesh Bisai
DOI:10.1021/acs.joc.8b01101
日期:2018.9.21
We report an efficient Pd(0)-catalyzed deacylative allylation of N-acyl 3-substituted 2-oxindoles via the coupling of in situ generated nucleophiles (3 and 4) with allyl electrophiles for the synthesis of a variety of 2-oxindoles with C3-quaternary centers. Gratifyingly, this alkylation process is found to be highly chemoselective in nature, where a C–C bond formation is completely predominant over
<i>L</i>-Pyroglutamic Sulphonamide as Hydrogen-Bonding Organocatalyst: Enantioselective Diels–Alder Cyclization to Construct Carbazolespirooxindoles
作者:Ji-Wei Ren、Jing Wang、Jun-An Xiao、Jun Li、Hao-Yue Xiang、Xiao-Qing Chen、Hua Yang
DOI:10.1021/acs.joc.7b00733
日期:2017.6.16
applied in catalyzing asymmetric Diels–Aldercyclization of methyleneindolinones with 2-vinyl-1H-indoles to efficiently assemble carbazolespirooxindoles in excellent stereoselectivity (up to 99% ee, >20:1 dr) and yields (up to 99%). Mechanistic studies disclosed that the well-designed hydrogen-bonding modes between L-pyroglutamic sulphonamide and substrates were crucial for stereocontrol in the cyclization