Intramolecular hydroaminations of aminoalkynes catalyzed by yttrium complexes and aminoallenes catalyzed by zirconium complexes

초록

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-d(6) at 120 degrees C for 5 days and 10 days, respectively, via elimination of (TMS)(2)NH. 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.

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