Copper(ii)-catalyzed synthesis of multisubstituted indoles through sequential Chan-Lam and cross-dehydrogenative coupling reactions
Starting from arylboronic acids and ester (Z)-3-aminoacrylates, one-pot syntheses of diverse indole-3-carboxylic esters have been described through copper(ii)-catalyzed sequential Chan-Lam N-arylation and cross-dehydrogenative coupling (CDC) reactions. The initial Chan-Lam arylation can proceed in DMF at 100 °C for 24 h to give ester (Z)-3-(arylamino)acrylate intermediates in the presence of Cu(OAc)2/tri-tert-butylphosphine tetrafluoroborate, a catalytic amount of myristic acid as the additive, KMnO4 and KHCO3. Sequentially, these in situ arylated intermediates can undergo an intramolecular oxidative cross-dehydrogenative coupling process in mixed solvents (DMF/DMSO = 2 : 1) at 130 °C to give C3-functionalized multi-substituted indole derivatives. This journal is
Highly enantioselective synthesis of β-amino acid derivatives by the lewis base catalyzed hydrosilylation of β-enamino esters
A study was conducted to demonstrate highly enantioselective synthesis of β-amino acid derivatives by the Lewis base catalyzed hydrosilylation of βenamino esters. It was found that these catalyst and its analogue displayed excellent activities and enantioselectivities in promoting hydrosilylation of N-aryl β-enamino esters. N-picolinoylpyrrolidine derivatives and N-picolioylephedrine were also evaluated in hydrosilylation of (Z)-methyl 3-phenyl-3-(phenylamino)acrylate. The generality of the Lewis base organocatalyzed hydrosilylation of various β-enamino esters were examined under the optimized conditions. It was observed that the catalytic system exhibited a high sensitivity to the N-substituents, while all the N-aryl β-enamino esters underwent the hydrosilylation smoothly to give corresponding β-amino esters.
REACTIONS OF METHYL 3-ARYL-2-PROPYONATES WITH NUCLEOPHILIC NITROGEN COMPOUNDS
Benzylamine reacts with methyl 3-phenyl-(IVa) and methyl 3-(p-methoxyphenyl)-(IVb)2-propynoates to give the corresponding N-benzyl-3-aryl-2-propynoic amides (Va and b).On the other hand, methyl 3-(p-chlorophenyl)-2-propynoate (IVc) give methyl (Z)-β-benzylamino-p-chlorocinnamate (VIa). p-Methylaminobenzene and p-methoxyaminobenzene react with IVa-c to give the corresponding methyl (Z)-β-(arylamino)cinnamates (VIb-g).Similarly, o-phenylenediamine gave with IVc, methyl (Z)-β-(o-aminoanilino)-p-chlorocinnamate (VII).Benzoylhydrazine reacts with IVa and b to give the corresponding 1H-3-aryl-1-benzoyl-5-hydroxypyrazole (VIIIa and b); VIIIa was converted into the known 3-phenylpyrazol-5-one by the action of concentrated hydrochloric acid.Benzamidine hydrochloride and IVa-c in the presence of aqueous sodium carbonate give the correesponding methyl (Z)-β-benzamidinocinnamates (IXa-c).
Moussa, G. E. M.,Basyouni, M. N.,Fouli, F. A.,Kandeel, K. A.
p. 167 - 174
(2007/10/02)
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