Abstract
Trialkylalanes, which are inert toward imines, undergo addition to them in the presence
of a catalytic amount of dichlorodicyclopentadienylzirconium(IV) (Cp2 ZrCl2 ). The reaction tolerates the presence of several functional groups in the starting
imine such as halo, amide, nitrile, and hydroxy groups. A possible reaction pathway
is proposed involving metallacyclic intermediates.
Key words
zirconium - catalysis - trialkylalanes - amine synthesis - imines
References
<A NAME="RC03905SS-1A">1a </A>
Gandon V.
Bertus P.
Szymoniak J.
Eur. J. Org. Chem.
2001,
3677
<A NAME="RC03905SS-1B">1b </A>
Gandon V.
Bertus P.
Szymoniak J.
Synthesis
2002,
1115
<A NAME="RC03905SS-2">2 </A>
Takahashi T.
Liu Y.
Xi C.
Huo S.
Chem. Commun.
2001,
31
<A NAME="RC03905SS-3A">3a </A>
Dzhemilev UM.
Vostrikova OS.
Sultanov RM.
Izv. Akad. Nauk SSSR, Ser. Khim.
1983,
218
<A NAME="RC03905SS-3B">3b </A>
Takahashi T.
Seki T.
Nitto Y.
Saburi M.
Rousset CI.
Negishi E.
J. Am. Chem. Soc.
1991,
113:
6266
<A NAME="RC03905SS-3C">3c </A>
Lewis DP.
Muller PM.
Whitby RJ.
Jones RVH.
Tetrahedron Lett.
1991,
32:
6797
Higher Grignard reagents react with alkenes only in the presence of an internal Lewis
base, see:
<A NAME="RC03905SS-4A">4a </A>
Hoveyda AH.
Morken JP.
Houri AF.
Xu Z.
J. Am. Chem. Soc.
1992,
114:
6692
<A NAME="RC03905SS-4B">4b </A>
Heron NM.
Adams JA.
Hoveyda AH.
J. Am. Chem. Soc.
1997,
119:
6205
<A NAME="RC03905SS-5">5 </A>
Negishi E.
Huo S. In
Titanium and Zirconium in Organic Synthesis
Marek I.
Wiley-VCH;
Weinheim:
2002.
Chap. 1.
<A NAME="RC03905SS-6A">6a </A>
Van Horn DE.
Negishi E.
J. Am. Chem. Soc.
1978,
100:
2252
<A NAME="RC03905SS-6B">6b </A>
Negishi E.
Van Horn DE.
Yoshida T.
J. Am. Chem. Soc.
1985,
107:
6639
<A NAME="RC03905SS-6C">6c </A>
Negishi E.
Kondakov DY.
Choueiry D.
Kasai K.
Takahashi T.
J. Am. Chem. Soc.
1996,
118:
957
<A NAME="RC03905SS-7A">7a </A>
Kondakov DY.
Negishi E.
J. Am. Chem. Soc.
1995,
117:
10771
<A NAME="RC03905SS-7B">7b </A>
Kondakov DY.
Negishi E.
J. Am. Chem. Soc.
1996,
118:
1577
<A NAME="RC03905SS-7C">7c </A> Negishi E.; Chem.-Eur. J. ; 1999 , 5: 411
<A NAME="RC03905SS-8A">8a </A>
Alberola A.
Cermeño FA.
Anton A.
An. Quim.
1977,
73:
886
Lanthanide-catalyzed addition of Et3 Al to aromatic Schiff bases has recently been reported, see:
<A NAME="RC03905SS-8B">8b </A>
Tsvelikhovsky D.
Gelman D.
Molander GA.
Blum J.
Org. Lett.
2004,
6:
1995
These reactions mainly involve the addition of organolithium and organozinc reagents
to imines under Lewis base, acid, or transition-metal catalysis, for reviews, see:
<A NAME="RC03905SS-9A">9a </A>
Denmark SE.
Nicaise OJ.-C. In
Comprehensive Asymmetric Catalysis
Jacobsen EN.
Pfaltz A.
Yamamoto H.
Springer;
Berlin:
1999.
p.923
<A NAME="RC03905SS-9B">9b </A>
Kobayashi S.
Ishitani H.
Chem. Rev.
1999,
99:
1069
<A NAME="RC03905SS-10">10 </A>
Ketimines proved to be inert toward Et3 Al in these conditions.
<A NAME="RC03905SS-11">11 </A>
In the case of the carboalumination (R ¹ Me) of alkenes, a mechanism switch from cyclic
to acyclic was noticed by changing from nonpolar to chlorinated solvents, see ref.
7.
<A NAME="RC03905SS-12">12 </A>
Gridd R.
McMeekin P.
Sridharan V.
Tetrahedron
1995,
51:
13331
<A NAME="RC03905SS-13">13 </A>
Ziegler K, and
Nagel K. inventors; US 2744127.
<A NAME="RC03905SS-14">14 </A>
Samec JSM.
Bäckvall J.-E.
Chem.-Eur. J.
2002,
8:
2955
<A NAME="RC03905SS-15">15 </A>
Chi Y.
Zhou Y.-G.
Zhang X.
J. Org. Chem.
2003,
68:
4120
<A NAME="RC03905SS-16">16 </A>
Wu M.-J.
Pridgen LN.
J. Org. Chem.
1991,
56:
1340
<A NAME="RC03905SS-17A">17a </A>
Motoyama Y.
Mikami H.
Kawakami H.
Aoki K.
Nishiyama H.
Organometallics
1999,
18:
3584
<A NAME="RC03905SS-17B">17b </A>
Nakagawa M.
Kaware T.
Kakikawa T.
Yamada H.
Matsui T.
Hino T.
Tetrahedron
1993,
49:
1739
<A NAME="RC03905SS-18">18 </A>
Micovic IV.
Ivanovic MD.
Piatak DM.
Bojic VD.
Synthesis
1991,
1043