Journal ArticleDOI
Zinc Salt Promoted Diastereoselective Synthesis of Chiral Propargylamines Using Chiral Piperazines and Their Enantioselective Conversion into Chiral Allenes.
Mariappan Periasamy,Polimera Obula Reddy,Athukuri Edukondalu,Manasi Dalai,Laxman M. Alakonda,Bantu Udaykumar +5 more
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TLDR
Unexpectedly, the chiral aryl-substituted allenes undergo facile cyclodimerization under neat conditions at 25 °C, in contrast to an earlier report that cyclodericization takes place at 80 °C in benzene, which further illustrates the importance of the two-step procedure reported herein becauseThe chiral propargylamine may be converted into chiral allene when required.Abstract:
Zinc chloride catalyzed reactions of chiral piperazine derivatives 4a–d with 1-alkynes and aldehydes give chiral propargylamines in 67–95 % yields with up to 99:1 dr. The chiral propargylamines are converted into chiral allenes by using zinc bromide in short reaction times (1–2 h) in high enantioselectivities (up to 99 % ee) in good yields (up to 89 %). The chiral piperazines are recovered in good yields (79–86 %) by reduction of the imine byproducts in situ by using NaBH4. Unexpectedly, the chiral aryl-substituted allenes undergo facile cyclodimerization under neat conditions at 25 °C, in contrast to an earlier report that cyclodimerization takes place at 80 °C in benzene, which further illustrates the importance of the two-step procedure reported herein because the chiral propargylamine may be converted into chiral allene when required.read more
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Synthesis, Structural Characterization, and Catalytic Property of A Zn(II) Complex with 5-Bromosalicylaldehyde Ligand
TL;DR: In this paper, a new six-coordination Zn(II) complex material, [ZnL 2 (H 2 O) 2 ] (C1) (HL = 5-bromosalicylaldehyde), has been prepared with 5 bromosalimylaldehyde, NaOH, and Zn (CH 3 COO) 2 ·2H 2O 2 O as raw materials, and its structure was determined by elemental analysis, IR spectra, and single crystal X-ray diffraction.
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Journal ArticleDOI
Zinc Salt Promoted Diastereoselective Synthesis of Chiral Propargylamines Using Chiral Piperazines and Their Enantioselective Conversion into Chiral Allenes
Mariappan Periasamy,Polimera Obula Reddy,Athukuri Edukondalu,Manasi Dalai,Laxman M. Alakonda,Bantu Udaykumar +5 more
TL;DR: Unexpectedly, the chiral aryl-substituted allenes undergo facile cyclodimerization under neat conditions at 25 °C, in contrast to an earlier report that cyclodericization takes place at 80 °C in benzene, which further illustrates the importance of the two-step procedure reported herein becauseThe chiral propargylamine may be converted into chiral allene when required.