LETTER
Molybdenum(VI) Dichloride Dioxide and its DMF Complex
2433
(6) (a) Evans, D. A. Aldrichimica Acta 1982, 15, 23. (b) Ager,
D. J.; Prakash, I.; Schaad, D. R. Chem. Rev. 1996, 96, 835.
(c) Sibi, M. P. Aldrichimica Acta 1999, 32, 93.
(7) For carbamate reviews, see: (a) Rossi, L. in ‘Four Carbon–
Heteroatom Bonds: X–C≡X, X=C=X, X2C=X, CX4’, Science
of Synthesis, Houben-Weyl Methods of Organic Chemistry,
Vol. 18; Knight, J. G., Ed.; Thieme: Stuttgart / New York,
2005, 461–648. (b) Chaturvedi, D.; Mishra, N.; Mishra, V.
Curr. Org. Synth. 2007, 4, 308.
(8) Hutton, C. A.; Bartlett, P. A. J. Org. Chem. 2007, 72, 6865.
(9) Nikiforov, A.; Jirovetz, L.; Buchbauer, G. Liebigs Ann.
Chem. 1989, 489.
(10) Varie, D. L.; Beck, C.; Borders, S. K.; Brady, M. D.; Cronin,
J. S.; Ditsworth, T. K.; Hay, D. A.; Hoard, D. W.; Hoying,
R. C.; Linder, R. J.; Miller, R. D.; Moher, E. D.; Remacle,
J. R.; Rieck, J. A. III.; Anderson, D. D.; Dodson, P. N.; Forst,
M. B.; Pierson, D. A.; Turpin, J. A. Org. Process Res. Dev.
2007, 11, 546.
Table 6 Carbamoylation of (–)-Menthol (16) with Representative
Isocyanates Catalyzed by MoO2Cl2(DMF)2
53
O
N R
O
8, 11, 14, 30–33
(1.2 equiv),
R
(−)-Menthyl OH
(−)-Menthyl
O
N
H
MoO2Cl2(DMF)2 (0.1 mol%),
CH2Cl2,
16
20, 34–39
r.t., time
([16]0 = 1.0 M)
R
Isocyanate Time (min) Carbamate Yielda
Bu
30
31
32
14
11
8
20
20
20
20
20
20
120
34
35
36
17
37
38
39
98%
Bn
quant.
quant.
quant.
quant.
90%
4-acetylphenyl
Ph
(11) Tsuji, T.; Nishida, S.; Okuyama, M.; Osawa, E. J. Am.
Chem. Soc. 1995, 117, 9804.
(12) Elman, B.; Moberg, C. Tetrahedron 1986, 42, 223.
(13) Keyes, R. F.; Carter, J. J.; Zhang, X.; Ma, Z. Org. Lett. 2005,
7, 847.
4-methoxyphenyl
cyclohexyl
t-Bub
33
quant.
a All reactions provided analytically pure carbamate after aqueous
workup and removal of the solvent.
(14) Cameron, J. F.; Willson, C. G.; Fréchet, J. M. J. J. Chem.
Soc., Perkin Trans. 1 1997, 2429.
b The reaction was carried out with 1.0 mol% of the catalyst.
(15) Andrade, R. B.; Martin, S. F. Org. Lett. 2005, 7, 5733.
(16) Duggan, M. I.; Imagire, J. S. Synthesis 1989, 131.
(17) Nishikawa, T.; Urabe, D.; Tomita, M.; Tsujimoto, T.;
Iwabuchi, T.; Isobe, M. Org. Lett. 2006, 8, 3263.
(18) Paleo, M. R.; Calaza, M. I.; Sardina, F. J. J. Org. Chem.
1997, 62, 6862.
bamoylation reactions proceeded to completion after 20
minutes at room temperature. Only tertiary substrates
needed more time and/or higher catalyst loadings for
reaching 90–100% yield like the less hindered substrates.
The purity of our carbamates after aqueous workup but
without chromatography was noteworthy. The mildness
of our procedure suggests that it may be applied advanta-
geously to many other polyfunctional substrates beside
our Michael acceptors 10 and (E,E)-13.
(19) Cameron, J. F.; Fréchet, J. M. J. J. Org. Chem. 1990, 55,
5919.
(20) Cate, A. T.; Dankers, P. Y. W.; Kooijman, H.; Spek, A. L.
J. Am. Chem. Soc. 2003, 125, 6860.
(21) Dillard, R. D.; Poore, G. A.; Easton, N. R.; Sweeney, M. J.;
Gibson, W. R. J. Med. Chem. 1968, 11, 1155.
(22) Spino, C.; Joly, M.-A.; Godbout, C.; Arbour, M. J. Org.
Chem. 2005, 70, 6118.
(23) Benalil, A.; Roby, P.; Carboni, B.; Vaultier, M. Synthesis
References and Notes
1991, 787.
(24) Villhauer, E. B.; Brinkman, J. A.; Naderi, G. B.; Burkey, B.
F.; Dunning, B. E.; Prasad, K.; Mangold, B. L.; Russell, M.
E.; Hughes, T. E. J. Med. Chem. 2003, 46, 2774.
(25) (a) Britain, J. W.; Gemeinhardt, P. G. J. Appl. Polym. Sci.
1960, 4, 207. (b) Francis, T.; Thorne, M. P. Can. J. Chem.
1976, 54, 24.
(26) White, D. K.; Greene, F. D. J. Org. Chem. 1978, 43, 4530.
(27) Kim, Y. H.; Park, H. S. Synlett 1998, 261.
(28) Hodgson, D. M.; Thompson, A. J.; Wadman, S.; Keats, C. J.
Tetrahedron 1999, 55, 10815.
(29) Finke, P. E.; Oates, B.; Mills, S. G.; MacCoss, M.;
Malkowitz, L.; Springer, M. S.; Gould, S. L.; DeMartino,
J. A.; Carella, A.; Carver, G.; Holmes, K.; Danzeisen, R.;
Hazuda, D.; Kessler, J.; Lineberger, J.; Miller, M.; Schleif,
W. A.; Emini, E. A. Bioorg. Med. Chem. Lett. 2001, 11,
2475.
(1) For polyurethane reviews, see: (a) Silva, A. L.; Bordado,
J. C. Catal. Rev. 2004, 46, 31. (b) Moratti, S. C.;
Charalambides, Y. C. ‘Polymeric Carbamic Acids and
Esters, and Their Sulfur Analogues’, in ‘Four Carbon–
Heteroatom Bonds: X–C≡X, X=C=X, X2C=X, CX4’, Science
of Synthesis, Houben-Weyl Methods of Organic Chemistry,
Vol. 18; Knight, J. G., Ed.; Thieme: Stuttgart / New York,
2005, 649–664.
(2) For example: Propamocarb and Carbaryl: Römpp Online,
Version 3.1; Georg Thieme Verlag: Stuttgart, 2008.
(3) (a) Rivastigmine: Winblad, B.; Grossberg, G.; Frölich, L.;
Farlow, M.; Zechner, S.; Nagel, J.; Lane, R. Neurology
2007, 69, 14. (b) Retigabine: Blackburn-Munro, G.; Dalby-
Brown, W.; Mirza, N. R.; Mikkelsen, J. D.; Blackburn-
Munro, R. E. CNS Drug Rev. 2005, 11, 1. (c) Pardoprunox:
Hauser, R. A.; Bronzova, J.; Sampaio, C.; Lang, A. E.;
Rascol, O.; Theeuwes, A.; van de Witte, S. V. Eur. Neurol.
2009, 62, 40.
(30) Review: Jeyakumar, K.; Chand, D. K. J. Chem. Sci. 2009,
121, 111.
(31) Jeyakumar, K.; Chand, D. K. Synthesis 2009, 306.
(32) Jeyakumar, K.; Chand, D. K. Synthesis 2008, 807.
(33) Jeyakumar, K.; Chand, D. K. Synthesis 2008, 1685.
(34) Weng, S.-S.; Lin, Y.-D.; Chen, C.-T. Org. Lett. 2006, 8,
5633.
(35) Goswami, S.; Maity, A. C. Tetrahedron Lett. 2008, 49, 3092.
(36) Chen, C.-T.; Kuo, J.-H.; Pawar, V. D.; Munot, Y. S.; Weng,
S.-S.; Ku, C.-H.; Liu, C.-Y. J. Org. Chem. 2005, 70, 1188.
(4) Snieckus, V. Chem. Rev. 1990, 90, 879.
(5) (a) Hoppe, D.; Hense, T. Angew. Chem., Int. Ed. Engl. 1997,
36, 2282; Angew. Chem., 1997, 109, 2376. (b) Beak, P.;
Johnson, T. A.; Kim, D. D.; Lim, S. H.Organolithiums in
Enantioselective Synthesis In Top. Organomet. Chem., Vol.
5; Hodgson, D. M., Ed.; 2003, 139–176.
Synlett 2010, No. 16, 2429–2434 © Thieme Stuttgart · New York