Catalytic asymmetric diamination of conjugated dienes and triene

Article abstract of DOI:10.1021/ja074698t

This paper describes a catalytic asymmetric diamination process using di-tert-butyldiaziridinone as nitrogen source with catalyst generated from Pd₂(dba)₃ and chiral phosphorus amidite ligand. A wide variety of conjugated dienes and

Full text of DOI:10.1021/ja074698t

Published on Web 09/06/2007
Catalytic Asymmetric Diamination of Conjugated Dienes and Triene
Haifeng Du, Weicheng Yuan, Baoguo Zhao, and Yian Shi*
Department of Chemistry, Colorado State UniVersity, Fort Collins, Colorado 80523
Received June 26, 2007; E-mail: yian@lamar.colostate.edu
Scheme 1
Vicinal diamines are very important functional moieties contained
in various biologically active compounds and are also effective
chiral control elements in asymmetric synthesis.1 Metal-mediated
and catalyzed diamination of olefins provides an effective approach
to the synthesis of vicinal diamines, and various diamination
systems have been developed.1-6 Chiral auxiliary-based7 and chiral
Lewis acid-catalyzed8 asymmetric diamination of R,â-unsaturated
Scheme 2
esters and related oxazolidinones using bisimidoosmium as reagent
have also been reported. Generally speaking, asymmetric diami-
nation of olefins with a catalytic amount of metal has yet to be
developed. Recently, we reported a Pd(0)-catalyzed regio- and
stereoselective diamination of conjugated dienes and trienes using
di-tert-butyldiaziridinone (2)9 as nitrogen source (Scheme 1).10,11
Herein we wish to report a catalytic asymmetric process for this
diamination.
Chart 1. Asymmetric Diamination of Diene 4 with Selected
Ligands
Asymmetric diamination was initially examined using 1,3-
hexadiene as substrate with catalysts generated from Pd2(dba)3 and
various commercially available or easily prepared chiral ligands in
C6D6 for 1.5 h (Scheme 2). Some of the results are summarized in
Chart 1. Phosphine and phosphite ligands L1-L3 gave 4-26%
ee.12 Studies with BINOL-based chiral phosphorus amidite ligands
L4-L613 showed that the steric bulkiness of the nitrogen substituent
has a large impact on both reactivity and enantioselectivity for the
diamination. In search for more effective ligands, it was found that
quantitative conversion and 92% ee were obtained with tetrameth-
ylpiperidine-derived ligand L7.14 Promising results were also
obtained with commercially available ligands L8 and L9,15 which
provide additional opportunities for further improvement.
Encouraged by the results obtained with ligand L7, asymmetric
diaminations of various conjugated dienes were subsequently
investigated. As shown in Table 1, a variety of conjugated dienes
can be diaminated in good yields and high enantioselectivities (87-
95% ee). Like racemic diaminations with Pd(PPh3)4,10,11 the reaction
occurred highly regioselectively at the internal double bond and
highly diastereoselectively, as well. When a mixture of E and Z
Scheme 3
dienes were used (Table 1, entries 2, 4-6, and 12), only E isomers
were diaminated. When a conjugated triene was used, the diami-
nation occurred cleanly at the middle double bond in high
enantioselectivity (Table 1, entry 14).16,17
The resulting cyclic ureas18 provide access to various optically
active diamine compounds. For example, free diamine 8 can be
obtained in high yield and ee from 6 by deprotection with CF3-
CO2H19 and HCl20 (Scheme 3).11 Olefins present in diamination
products also provide good opportunities for further elaboration.
For example, compound 6 can be readily converted into optically
active 2,3-diamino acid 1120 by oxidation of the olefin21 and
deprotection (Scheme 3).22 The selective monodeprotection of 9
was also achieved cleanly to give 12 with CF3CO2H at rt,10
providing opportunities to introduce different groups on the
nitrogens if desired.23
In summary, a catalytic asymmetric diamination for a variety of
conjugated dienes and triene has been effectively achieved using
di-tert-butyldiaziridinone as nitrogen source with a catalyst gener-
ated from Pd2(dba)3 and tetramethylpiperidine-derived phosphorus
amidite ligand L7, giving diamination products in good yields with
9
11688
J. AM. CHEM. SOC. 2007, 129, 11688-11689
10.1021/ja074698t CCC: $37.00 © 2007 American Chemical Society

C O M M U N I C A T I O N S
Table 1. Catalytic Asymmetric Diamination of Dienes and Trienea
catalysts, and chiral ligands as well as expansion of the substrate
scope and synthetic application is currently underway.
Acknowledgment. We are grateful for the generous financial
support from Camille and Henry Dreyfus Foundation.
Supporting Information Available: Experimental procedures,
characterizations, and data for determination of enantiomeric excess
1
of diamination products and their derivatives along with the H and
13C NMR spectra of compounds. This material is available free of
charge via the Internet at http://pubs.acs.org.
References
(1) For leading reviews, see: (a) Lucet, D.; Gall, T. L.; Mioskowski, C. Angew.
Chem., Int. Ed. 1998, 37, 2580. (b) Mortensen, M. S.; O’Doherty, G. A.
Chemtracts: Org. Chem. 2005, 18, 555. (c) Kotti, S. R. S. S.; Timmons,
C.; Li, G. Chem. Biol. Drug Des. 2006, 67, 101.
(2) For examples of metal-mediated diaminations, see: Co: (a) Becker, P.
N.; White, M. A.; Bergman, R. G. J. Am. Chem. Soc. 1980, 102, 5676.
Hg: (b) Barluenga, J.; Alonso-Cires, L.; Asensio, G. Synthesis 1979, 962.
Mn: (c) Fristad, W. E.; Brandvold, T. A.; Peterson, J. R.; Thompson, S.
R. J. Org. Chem. 1985, 50, 3647. Os: (d) Chong, A. O.; Oshima, K.;
Sharpless, K. B. J. Am. Chem. Soc. 1977, 99, 3420. (e) Mun˜iz, K. Eur. J.
Org. Chem. 2004, 2243. Pd: (f) Ba¨ckvall, J.-E. Tetrahedron Lett. 1978,
163. Tl: (g) Aranda, V. G.; Barluenga, J.; Aznar, F. Synthesis 1974, 504.
(3) For a recent Cu(II)-mediated intramolecular diamination, see: (a) Zabawa,
T. P.; Kasi, D.; Chemler, S. R. J. Am. Chem. Soc. 2005, 127, 11250. (b)
Zabawa, T. P.; Chemler, S. R. Org. Lett. 2007, 9, 2035.
(4) For Rh(II)- and Fe(III)-catalyzed diamination with TsNCl2, see: (a) Li,
G.; Wei, H.-X.; Kim, S. H.; Carducci, M. D. Angew. Chem., Int. Ed. 2001,
40, 4277. (b) Wei, H.-X.; Kim, S. H.; Li, G. J. Org. Chem. 2002, 67,
4777.
(5) For a recent Pd(II)-catalyzed intermolecular diamination of conjugated
dienes, see: Bar, G. L. J.; Lloyd-Jones, G. C.; Booker-Milburn, K. I. J.
Am. Chem. Soc. 2005, 127, 7308.
(6) For a recent Pd(II)-catalyzed intramolecular diamination of terminal olefins,
see: Streuff, J.; Ho¨velmann, C. H.; Nieger, M.; Mun˜iz, K. J. Am. Chem.
Soc. 2005, 127, 14586.
(7) (a) Mun˜iz, K.; Nieger, M. Synlett 2003, 211. (b) Mun˜iz, K.; Iesato, A.;
Nieger, M. Chem.sEur. J. 2003, 9, 5581.
(8) (a) Mun˜iz, K.; Nieger, M. Chem. Commun. 2005, 2729. (b) Almodovar,
I.; Ho¨velmann, C. H.; Streuff, J.; Nieger, M.; Mun˜iz, K. Eur. J. Org.
Chem. 2006, 704.
(9) Greene, F. D.; Stowell, J. C.; Bergmark, W. R. J. Org. Chem. 1969, 34,
2254.
(10) Du, H.; Zhao, B.; Shi, Y. J. Am. Chem. Soc. 2007, 129, 762.
(11) Du, H.; Yuan, W.; Zhao, B.; Shi, Y. J. Am. Chem. Soc. 2007, 129, 7496.
(12) For leading references on L1-L3, see: (a) Morrison, J. D.; Burnett, R.
E.; Aguiar, A. M.; Morrow, C. J.; Phillips, C. J. Am. Chem. Soc. 1971,
93, 1301. (b) Hattori, T.; Shijo, M.; Kumagai, S.; Miyano, S. Chem.
Express 1991, 6, 335. (c) Uozumi, Y.; Hayashi, T. J. Am. Chem. Soc.
1991, 113, 9887. (d) Grubbs, R. H.; DeVries, R. A. Tetrahedron Lett.
1977, 1879.
(13) For leading references on L4-L6, see: (a) de Vries, A. H. M.; Meetsma,
A.; Feringa, B. L. Angew. Chem., Int. Ed. Engl. 1996, 35, 2374. (b)
Sewald, N.; Wendisch, V. Tetrahedron: Asymmetry 1998, 9, 1341. (c)
Arnold, L. A.; Imbos, R.; Mandoli, A.; de Vires, A. H. M.; Naasz, R.;
Feringa, B. L. Tetrahedron 2000, 56, 2865.
(14) A ratio of 1:2.2 for Pd/L7 was found to be optimal for the conversion.
Similar ee’s with somewhat lower conversion were obtained in toluene.
(15) For leading references on L8 and L9, see: (a) Keller, E.; Maurer, J.;
Naasz, R.; Schader, T.; Meetsma, A.; Feringa, B. L. Tetrahedron:
Asymmetry 1998, 9, 2409. (b) Zhou, H.; Wang, W.-H.; Fu, Y.; Xie, J.-
H.; Shi, W.-J.; Wang, L.-X.; Zhou, Q.-L. J. Org. Chem. 2003, 68, 1582.
(16) No diamination at allylic and homoallylic carbons was observed with alkyl-
substituted dienes under the current reaction conditions.
a All reactions were carried out with diene or triene (0.40 mmol),
diaziridinone 2 (0.50 mmol), Pd2(dba)3 (0.02 mmol), and L7 (0.088 mmol)
in benzene-d6 (0.2 mL) in an NMR tube at 65 °C under argon for 1.5 h
unless otherwise stated. b A mixture of E and Z isomers was used. For entry
2, diene (0.88 mmol, E/Z ) 1/1.2, E isomer: 0.40 mmol); for entry 4,
diene (1.0 mmol, E/Z ) 1/1.5, E isomer: 0.40 mmol); for entry 5, diene
(0.73 mmol, E/Z ) 1.2/1, E isomer: 0.40 mmol); for entry 6, diene (0.64
mmol, E/Z ) 1.67/1, E isomer: 0.40 mmol); for entry 12, diene (0.64 mmol,
E/Z ) 1.67/1, E isomer: 0.40 mmol). c The reaction time was 2 h. d For
entry 4, the absolute configuration (R,R) was determined by comparing the
optical rotation with the reported one after removal of t-butyl groups (ref
21). For the rest, the absolute configurations are not determined, and the
stereochemistry indicated represents the relative stereochemistry. e Isolated
yield based on diene or triene. f The ee was determined by chiral GC
(Chiraldex B-DM column) after removal of t-butyl group. g The ee was
determined by chiral GC (Chiraldex B-DM column). h The ee was
determined by chiral HPLC (Chiralpak AD-H column). i The ee was
determined by chiral HPLC (Chiralpak AD column) after removal of t-butyl
groups.
(17) Styrene was not an effective substrate, and a small amount of diamination
product at allylic and homoallylic carbons was formed with 1-hexene under
the current reaction conditions.
(18) For a leading reference on biologically active cyclic ureas, see: Kim,
M.; Mulcahy, J. V.; Espino, C. G.; Du Bois, J. Org. Lett. 2006, 8, 1073.
(19) Clayden, J.; Menet, C. J. Tetrahedron Lett. 2003, 44, 3059.
(20) Dunn, P. J.; Ha¨ner, R.; Rapoport, H. J. Org. Chem. 1990, 55, 5017.
(21) Oshitari, T.; Akagi, R.; Mandai, T. Synthesis 2004, 1325.
(22) Diamino acids are present in many biologically active molecules; for
examples, see: (a) Shigematsu, N.; Setoi, H.; Uchida, I.; Shibata, T.;
Terano, H.; Hashimoto, M. Tetrahedron Lett. 1988, 29, 5147. (b)
Kuwahara, A.; Nishikiori, T.; Shimada, N.; Nakagawa, T.; Fukazawa, H.;
Mizuno, S.; Uehara, Y. J. Antibiot. 1997, 50, 712. (c) Lee, J.-C.; Kim, G.
T.; Shim, Y. K.; Kang, S. H. Tetrahedron Lett. 2001, 42, 4519.
(23) The ee of 8 was determined after being converted into diamide; the ee’s
of 10 and 12 were determined after being converted into methyl esters.
high regio-, diastereo-, and enantioselectivities. The resulting
diamination products are potentially valuable intermediates for the
synthesis of various optically active compounds such as diamine,
2,3-diamino acid. Further development of a more effective asym-
metric catalytic process using different nitrogen sources, metal
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