An easy-to-use, regioselective, and robust bis(amidate) titanium hydroamination precatalyst: mechanistic and synthetic investigations toward the preparation of tetrahydroisoquinolines and benzoquinolizine alkaloids.
Amidate-supported titanium amido complexes are efficient and regioselective precatalysts for intermolecular hydroamination of terminal alkynes with primary amines. The synthesis and characterization of the first bis(amidate)-supported titanium-imido complex is reported. Its role as the active catalytic species is suggested in the course of product distribution studies using deuterated substrates. The bis(amidate)-supported precatalysts exhibit good functional-group tolerance, even performing hydroaminations in the presence of ester and amide groups. This functional-group tolerance was exploited in the synthesis of a variety of 1-substituted tetrahydroisoquinoline alkaloids and a one-pot hydroaminative procedure for the high yielding preparation of the benzo[a]quinolizine skeleton.
Zhang
Zhe
Z
Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T 1Z1, Canada.
Leitch
David C
DC
Lu
Man
M
Patrick
Brian O
BO
Schafer
Laurel L
LL
D000470:Alkaloids / Q000138:chemical synthesis / Q000737:chemistry*; D000586:Amination; D002384:Catalysis; D002625:Chemistry, Organic / Q000379:methods*; D015394:Molecular Structure; D009942:Organometallic Compounds; D011804:Quinolines / Q000138:chemical synthesis* / Q000737:chemistry; D044005:Tetrahydroisoquinolines / Q000138:chemical synthesis / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*
D000470:Alkaloids; D009942:Organometallic Compounds; D011804:Quinolines; D044005:Tetrahydroisoquinolines; D014025:Titanium