Internal Alkene Hydroaminations Catalyzed by Zirconium(IV) Complexes and Asymmetric Alkene Hydroaminations Catalyzed by Yttrium(III) Complexes

✍ Scribed by Hyunseok Kim; Young Kwan Kim; Jun Hwan Shim; Misook Kim; Mijung Han; Tom Livinghouse; Phil Ho Lee

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 182 KB
• Volume: 348
• Category: Article
• ISSN: 1615-4150
• DOI: 10.1002/adsc.200606171

✦ Synopsis

The thiophosphinic amide 2 was prepared in 68 % yield by the reaction of 2,2-dimethyl-1,3-propanediamine with diisopropylchlorophosphine followed by the addition of sulfur. Attachment of the proligand 2 to zirconium was achieved by direct metalation with ZrA C H T U N G T R E N N U N G (NMe 2 ) 4 in benzene-d 6 or toluene-d 8 to afford complex 3 via elimination of dimethylamine. The neutral Zr(IV) complex 3 has been shown to be an effective precatalyst for intramolecular alkene hydroaminations that provide cyclic amines in good to excellent yields. A variety of chiral ligands (20, 22, 24, and 25-30) were prepared for asymmetric internal alkene hydroaminations. Metalation of chiral ligands to yttrium was accomplished with Y[N-A C H T U N G T R E N N U N G (TMS) 2 ] 3 in benzene-d 6 or toluene-d 8 to give complexes. Treatment of 7 with 5 mol % of 33 in benzene-d 6 (25 8C, 18 h) or toluene-d 8 (25 8C, 15 h) afforded 2,4,4-trimethylpyrrolidine 14 in 95 % yield (61 % ee).