- Asymmetric transfer hydrogenation of heterocycle-containing acetophenone derivatives using N-functionalised [(benzene)Ru(II)(TsDPEN)] complexes
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The application of enantiomerically-pure ruthenium(II) catalysts containing N - functionalised TsDPEN ligand to the asymmetric transfer hydrogenation of 15 examples of α-heterocyclic acetophenone derivatives is reported. Products of up to 99% ee were formed.
- Barrios-Rivera, Jonathan,Xu, Yingjian,Clarkson, Guy J.,Wills, Martin
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- Synthesis, characterization and catalytic application of Bi2S3 microspheres for Suzuki-Miyaura cross-coupling reaction and chemoselective ring opening of epoxides
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Bismuth sulfide (Bi2S3) prepared using L-cysteine, which served as both the sulfur source and the directing molecule for the formation of Bi2S3 as heterogeneous catalyst through solvothermal method. The prepared catalyst was examined by various techniques such as XRD, BET, FE-SEM, TEM, and TGA analysis. The results and analysis revealed that bismuth microspheres have better catalytic behavior for the preparation of biphenyl in water as a greenest solvent and for the ring opening of epoxides by nucleophiles including amines, alcohol, and thiol compared to pure Bi(NO3)3. 3H2O under solvent-free condition. Moreover, the novel catalyst could be recovered and reusedat least four times without loss of its catalytic activity.
- Ghorbani-Choghamarani, Arash,Taherinia, Zahra
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- Acid-catalyzed highly diastereoselective and effective synthesis of 1,3-disubstituted tetrahydropyrano[3,4-b]indoles
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We successfully explored for the first time that trifluoroacetic acid (TFA) can effectively catalyze the oxa-Pictet-Spengler reaction of secondary tryptophols and acetals to synthesize 1,3-disubstituted 1,3,4,9-tetrahydropyrano[3,4-b]indoles in high yield (up to >99%) and diastereoselectivity (>20:1). The secondary tryptophols were synthesized from indole-3-acetic acid. The one-pot synthesis of tetrahydropyrano[3,4-b]indoles was successfully developed from secondary tryptophols and in situ prepared acetals from aldehydes and trimethylorthoformate and thus the cost-efficiency of the protocol was effectively enhanced. Finally, the catalytic asymmetric synthesis of the 1,3-disubstituted tetrahydropyrano[3,4-b]indole was also demonstrated after enantioselective achievement of highly enantiopure secondary tryptophols.
- Wang, Pei,Zhao, Jia-Zhen,Li, Hong-Feng,Liang, Xiang-Ming,Zhang, Ya-Lun,Da, Chao-Shan
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supporting information
p. 129 - 133
(2016/12/23)
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- A versatile synthetic methodology for the synthesis of tryptophols
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Tryptophols have been obtained in high yields by the reduction of 3-substituted-dioxindoles (obtained by the aldol condensation reaction of ketones with isatins or by a modified Knovenagel malonate condensation) using a borane tetrahydrofuran complex. The reported methodology offers distinct advantages over existing methods for the synthesis of these compounds, including consistently greater yields, diastereoselective syntheses and the possibility for the synthesis of a wide range of structurally different tryptophols. The reduction reaction was found to proceed via an intermediate 1,3-diol-oxindole, which was obtained diastereoselectively and, which was subsequently reduced to the corresponding tryptophol.
- Garden, Simon J,Da Silva, Rosangela B,Pinto, Angelo C
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p. 8399 - 8412
(2007/10/03)
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