(vicinal diamine as a source of chirality; precursor for the synthesis of bidentate ligands)
Physical Data: bp 240°C; [a]D25-15 (c 0.145, CH2Cl2).
Solubility: most organic solvents.
Form Supplied in: colorless liquid; not commercially available.
Purification: shake with powdered K2CO3 in diethyl ether, filter, concentrate, and distill under reduced pressure.
Analysis of Reagent Purity: 1H and 13C NMR.
Handling, Storage, and Precautions: store under argon or nitrogen atmosphere; may be corrosive, like other vicinal diamines.
Preparative Methods: although syntheses of enantiomerically pure diamines have been developed mainly through resolution of racemic diamines, few methods have been reported for the diastereoselective synthesis of vicinal diamines. In particular, the addition of Grignard or zinc reagents to the carbon-nitrogen double bonds of chiral 1,2-bisimines1 derived from glyoxal and (S)- or (R)-phenethylamine, followed by removal of the phenethyl group, has been shown to be an attractive alternative method. Following a similar procedure, 1,2-diamino-1,2-di-tert-butylethane 3 can be synthesized in an optically pure form in three steps, as the R,R- or S,S-enantiomer, starting, respectively, from glyoxal and (S)- or (R)-phenethylamine.2 Indeed, addition of the chiral (S,S)-1,2-bis-imine 1 to a suspension of tert-butylmagnesium chloride in hexane at 50°C leads cleanly and in good yield to a single diastereomer of the (R,R)-diamine (2) (eq 1).
Deprotection of the chiral auxiliary groups is performed using ammonium formate, acetic acid, and palladium hydroxide in refluxing ethanol (eq 2
). This sequence gives, after purification by distillation, the free optically pure (R
´-dimethyl derivative 4
is obtained in three steps by formation of the corresponding imidazolidine with acetone, alkylation with iodomethane, and hydrolysis (eq 3
-tosyl derivative 5
, a possible precursor for the synthesis of ruthenium hydrogen transfer catalysts of type 6
is obtained in good yield by slow addition of TsCl in dichloromethane at 0°C (eq 4
Many asymmetric syntheses have been developed using vicinal diamines as the source of chirality. The major interest lies in their use as precursors for the synthesis of a broad family of bidentate ligands.5 Many reactions have also been described using the N-alkyl derivatives of these diamines as chiral auxiliaries and protecting groups of aldehydes.6 Most of these applications generally use the framework of 1,2-diphenyl-1,2-diaminoethane (7) or 1,2-diaminocyclohexane (8), whose preparations have been fully described.7
However, 1,2-diamino-1,2-di-tert-butylethane (3) holds particular interest because of its increased steric bulk and the absence of benzylic protons. Its recent ready availability should render it as attractive as the frequently used vicinal diamines 7 and 8. To our knowledge, only one application of this diamine has been previously described in the literature (eq 5),3b where the regio- and enantioselective epoxidation of conjugated aliphatic dienes were studied using the chiral manganese salen complex (9).
- 1. (a) Tom Dieck, H.; Dietrich, J., Chem. Ber. 1984, 117, 694. (b) Neumann, W. L.; Rogic, M. M.; Dunn, T. J., Tetrahedron Lett. 1991, 32, 5865. (c) Alvaro, J.; Grepioni, F.; Savoia, D., J. Org. Chem. 1997, 62, 4180. (d) Alexakis, A.; Tomassini, A.; Chouillet, C.; Roland, S.; Mangeney, P.; Bernardinelli, G., Angew. Chem., Int. Ed. Engl. 2000, 39, 4093.
- 2. (a) Roland, S.; Mangeney, P.; Alexakis, A., Synthesis 1999, 228. (b) Roland, S.; Mangeney, P., Eur. J. Org. Chem. 2000, 611.
- 3. To our knowledge, the only method previously described for the synthesis of 3 involved the coupling of a nitrile or an N-(trimethylsilyl)imine, promoted by NbCl4(THF). In this procedure the (+)-diamine was obtained pure in 18% yield by resolution with (-)-mandelic acid: (a) Roskamp, E. J.; Pedersen, S. F., J. Am. Chem. Soc. 1987, 109, 3152. (b) Rasmussen, K. G.; Thomsen, D. S.; Jørgensen, K. A., J. Chem. Soc., Perkin Trans 1 1995, 2009.
- 4. (a) Murata, K.; Ikariya, T., J. Org. Chem. 1999, 64, 2186. (b) Murata, K.; Okano, K.; Miyagi, M.; Iwane, H.; Noyori, R.; Ikariya, T., Org. Lett. 1999, 7, 1119. (c) Uematsu, N.; Fujii, A.; Hashiguchi, S.; Ikariya, T.; Noyori, R., J. Am. Chem. Soc. 1996, 118, 4916.
- 5. (a) Tomioka, K., Synthesis 1990, 541. (b) Corey, E. J.; Sarshar, S.; Bordner, J., J. Am. Chem. Soc. 1992, 114, 7938. (c) Corey, E. J.; Kim, S. S., J. Am. Chem. Soc. 1990, 112, 4976. (d) Bennani, Y. L.; Hanessian, S., Chem. Rev. 1997, 97, 3161. (e) Jacobsen, E. J. In Catalytic Asymmetric Synthesis; Ojima, I., Ed.; VCH, 1993, p 159-179. (f) Katsuki, T., J. Mol. Cat. 1996, 113, 87. (g) Mukaiyama, T., Aldrichimica Acta 1996, 29, 59. (h) Mukaiyama, T.; Yamada, T., Bull. Chem. Soc. Jpn 1995, 68, 17 and 1455. (i) Trost, B. M.; Van Vrancken, D. L., Chem. Rev. 1996, 96, 395. (j) Lucet, D.; Le Gall, T.; Mioskowski, C., Angew. Chem., Int. Ed. Engl. 1998, 37, 2580.
- 6. (a) Alexakis, A.; Mangeney, P. In Advanced Asymmetric Synthesis; Stephenson, G. R., Ed.; Chapman & Hall, London, UK, 1996; p 93. (b) Barettm A, G, M.; Doubledaym W. W.; Tustin, G. J.; White, A. J. P.; Williams, D. J., J. Chem. Soc., Chem. Commun. 1994, 2739.
- 7. For the diamine 4, see: (a) Pini, D.; Iuliano, A.; Rosini, C.; Salvadori, P., Synthesis 1990, 1023. (b) Lohray, B. B.; Ahuja, J. R., J. Chem. Soc., Chem. Commun. 1991, 95. (c) Oi, R.; Sharpless, K. B., Tetrahedron Lett. 1991, 32, 999. (d) Corey, E. J.; Imwinkelried, R.; Pikul, S.; Xiang, Y. B., J. Am. Chem. Soc. 1989, 111, 4486. (e) Shimizu, M.; Kamei, M.; Fujisawa, T., Tetrahedron Lett. 1995, 36, 8607. For the diamine 5, see: (f) Wieland, A.; Schlichtung, O.; Langsdorf, W. V. Z., Phys. Chem. 1926, 161, 74. (g) Swift, G.; Swern, D., J. Org. Chem. 1967, 32, 511. (h) Whitney, T. A., J. Org. Chem. 1980, 45, 4214.
Sylvain Roland & Pierre Mangeney
Université Pierre et Marie Curie, Paris, France
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