ORGANIC
LETTERS
2002
Vol. 4, No. 17
2853-2856
Intermolecular Alkyne Hydroaminations
Involving 1,1-Disubstituted Hydrazines
Changsheng Cao, Yanhui Shi, and Aaron L. Odom*
Department of Chemistry, Michigan State UniVersity, East Lansing, Michigan 48824
Received May 23, 2002
ABSTRACT
Two readily prepared catalysts have been developed for the hydroamination of alkynes by 1,1-disubstituted hydrazines. The catalyses are
facile with terminal alkynes and some internal alkynes. If the hydrazine bears an aryl group, Fischer cyclization can occur in a one-pot
procedure. In addition, reactions with acetylene to produce a plethora of hydrazones are described. Catalytic reactions involving acetylene
and substituted hydrazines are complete in less than 2 h at room temperature and 1 atm of pressure.
Intermolecular hydroamination1 of alkynes2 by primary
amines is a method for generating Schiff bases with perfect
atom economy. Several catalysts, spanning much of the
periodic table, have been utilized in the hydroamination of
alkynes. Of particular interest have been catalysts incorporat-
ing rhodium,3 palladium,4 ruthenium,5 lanthanides,6 ac-
tinides,7 and titanium.8,9
In this report, we describe catalysts for the direct addition
of 1,1-dialkyl-substituted hydrazines to unactivated10 alkynes,
a new catalytic transformation.11 Group IV hydroamination
(5) Tokunaga, M.; Eckert, M.; Wakatsuki, Y. Angew. Chem., Int. Ed.
1999, 38, 3222-3225.
(6) (a) Li, Y.; Marks, T. J. J. Am. Chem. Soc. 1998, 120, 1757-1771.
(b) Li, Y.; Marks, T. J. Organometallics 1996, 15, 3770-3772.
(7) (a) Straub, T.; Haskel, A.; Neyroud, T. G.; Kapon, M.; Botoshansky,
M.; Eisen, M. S. Organometallics 2001, 20, 5017-5035. (b) Haskel, A.;
Straub, T.; Eisen, M. S. Organometallics 1996, 15, 3773-3775. (c) Straub,
T.; Frank, W.; Reiss, G. J.; Eisen, M. S. J. Chem. Soc., Dalton Trans. 1996,
2541-2546.
(1) Reviews relevant to hydroamination: (a) Mu¨ller, T. E.; Beller, M.
Chem. ReV. 1998, 98, 675-703. (b) Roundhill, D. M. Chem. ReV. 1992,
92, 1. (c) Bryndza, H. E.; Tam, W. Chem. ReV. 1988, 88, 1163.
(2) Leading examples of intermolecular hydroamination of alkenes: (a)
Hartung, C. G.; Breindl, C.; Tillack, A.; Beller, M. Tetrahedron 2000, 56,
5157-5162. (b) Kawatsura, M.; Hartwig, J. F. J. Am. Chem. Soc. 2000,
122, 9546-9547. (c) Beller, M.; Trauthwein, H.; Eichberger, M.; Breindl,
C.; Mu¨ller, T. E. Eur. J. Inorg. Chem. 1999, 1121-1132. (d) Trauthwein,
H.; Tillack, A.; Beller, M. Chem. Commun. 1999, 2029-2030. (e) Beller,
M.; Trauthwein, H.; Eichberger, M.; Breindl, C.; Herwig, J.; Mu¨ller, T. E.;
Thiel, O. R. Chem. Eur. J. 1999, 5, 1306-1319. (f) Beller, M.; Trauthwein,
H.; Eichberger, M.; Breindl, C.; Mu¨ller, T. E.; Zapf, A. J. Organomet. Chem.
1998, 566, 277-286. (g) Beller, M.; Eichberger, M.; Trauthwein, H. Angew.
Chem., Int. Ed. Engl. 1997, 36, 2225-2226.
(8) (a) Pohlki, F.; Doye, S. Angew. Chem., Int. Ed. 2001, 40, 2305-
2308. (b) Johnson, J. S.; Bergman, R. G. J. Am. Chem. Soc. 2001, 123,
2923-2924. (c) Siebeneicher, H.; Doye, S. J. Prakt. Chem. Chem. Ztg.
2000, 341, 102-106. (d) Haak, E.; Bytschkov, I.; Doye, S. Angew. Chem.,
Int. Ed. 1999, 38, 3389-3391. (e) Bytschkov, I.; Doye, S. Eur. J. Org.
Chem. 2001, 4411-4418. (f) Shi, Y.; Ciszewski, J. T.; Odom, A. L.
Organometallics 2001, 20, 3967-3969. (g) Cao, C.; Ciszewski, J. T.; Odom,
A. L. Organometallics 2001, 20, 5011-5013.
(9) Seminal mechanistic studies on Group IV metal-catalyzed hydroami-
nation: (a) Straub, B. F.; Bergman, R. G. Angew. Chem., Int. Ed. 2001,
40, 4632-4635. (b) Sweeney, Z. K.; Salsman, J. L.; Anderson, R. A.;
Bergman, R. G. Angew. Chem., Int. Ed. 2000, 39, 2339-2343. (c) Polse,
J. L.; Anderson, R. A.; Bergman, R. G. J. Am. Chem. Soc. 1998, 120,
13405-13414. (d) Baranger, A. M.; Walsh, P. J.; Bergman, R. G. J. Am.
Chem. Soc. 1993, 115, 2753-2763. (e) Walsh, P. J.; Baranger, A. M.;
Bergman, R. G. J. Am. Chem. Soc. 1992, 114, 1708-1719.
(3) Hartung, C. G.; Tillack, A.; Trauthwein, H.; Beller, M. J. Org. Chem.
2001, 66, 6339-6343.
(4) (a) Kadota, I.; Shibuya, A.; Lutete, L. M.; Yamamoto, Y. J. Org.
Chem. 1999, 64, 4570-4571. (b) Yamamoto, Y.; Radhakrishnan, U. Chem.
Soc. ReV. 1999, 28, 199-207.
10.1021/ol0201052 CCC: $22.00 © 2002 American Chemical Society
Published on Web 07/26/2002