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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 28, Number 7
BKCSDE 28(7)
July 20, 2007 

 
Title
Intramolecular Hydroaminations of Aminoalkynes Catalyzed by Yttrium Complexes and Aminoallenes Catalyzed by Zirconium Complexes
Author
Hyunseok Kim, T. Livinghouse*, Dong Seomoon, Phil Ho Lee*
Keywords
Intramolecular hydroamination, Aminoalkyne, Aminoallene, Yttrium, Zirconium
Abstract
It was demonstrated that Y[N(TMS)2]3, the neutral yttrium-diamine complex 13 and yttrium-NPS complexes 15 are efficient precatalysts for intramolecular hydroamination of aminoalkynes involving primary amines. Complex 13 and 15 were quantitatively prepared in situ by direct metalation of the ligands 4 and 9 with 1 equiv of Y[N(TMS)2]3 in benzene-d6 at 120 oC for 5 days and 10 days, respectively, via elimination of (TMS)2NH. 5-Exo- and 6-exo-dig intramolecular hydroamination of aminoalkynes using catalyst 12 and 13 proceeded smoothly to give nitrogen-contained cyclic products in good to excellent yields in all cases. In the case of 7- exo-dig intramolecular hydroamination, the desired product was produced in 41% and 48% yields despite the gem-dimethyl effect. However, treatment of catalyst 15 with aminoalkynes (19 and 22) having a methyl substituent at the carbon adjacent to triple bond and 6-exo-dig intramolecular hydroamination of 21 failed to give the desired products. Zirconium-catalyzed intramolecular hydroamination of aminoallenes (25, 27, and 31) with 5 mol% 16 afforded 2-(trans-1-propenyl)pyrrolidine, 2-isopropylenepyrrolidine, and 2-(trans-1- propenyl)piperidine in 96%, 95%, and 93% yield, respectively. However, subjecting 25 to 5 mol% 15 was unsuccessful to produce the desired product.
Page
1127 - 0
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