J. Am. Chem. Soc. 1996, 118, 915-916
Nitrogen Transfer from a Nitridomanganese(V) Complex: Amination of Silyl Enol Ethers
915
Scheme 1
J. Du Bois,† Jason Hong,† Erick M. Carreira,*,† and Michael W. Day‡ Contribution No. 9155, Arnold and Mabel Beckman Laboratory for Chemical Synthesis and Beckman Institute, X-Ray Crystallography Laboratory California Institute of Technology Pasadena, California 91125 ReceiVed October 31, 1995 Metal-catalyzed oxygen atom-transfer reactions are of fundamental interest in both chemistry and biology.1 Detailed investigations of the mechanism of oxygen atom transfer in biological systems have led to the generation of synthetic models capable of performing analogous oxidation chemistry.2 This work has fueled the development of valuable synthetic methodology specifically with regard to alkene epoxidation, a reaction for which numerous protocols exist.3 In contrast, fewer methods are available for the related metal-mediated nitrogen atom-transfer reaction, despite the utility of such technology in synthesis.4,5 Herein, we describe the preparation of two novel nitridomanganese(V) salen-derived complexes that can be activated for nitrogen transfer with trifluoroacetic anhydride (TFAA).6,7 When this activation process is conducted in the presence of certain silyl enol ethers, rapid formation of N-trifluoroacetyl R-amino ketone products is observed (eq 1).
In one of the earliest examples of nitrogen atom-transfer chemistry, Groves and Takahashi elegantly described the use of nitrido[meso-tetrakis(2,4,6-trimethylphenyl)porphyrinato]manganese(V), (TMPMnN), for the aziridination of cis-cyclooctene.8 Formation of TMPMnN was effected by irradiation † ‡
Arnold and Mabel Beckman Laboratory for Chemical Synthesis. Beckman Institute, X-Ray Crystallography Laboratory. (1) (a) Sheldon, R. A.; Kochi, J. K. Metal-Catalyzed Oxidations of Organic Compounds; Academic: New York, 1981. (b) Feig, A. L.; Lippard, S. J. Chem. ReV. 1994, 94, 759. (c) Collman, J. P.; Zhang, X.; Lee, V. J.; Uffelman, E. S.; Brauman, J. I. Science 1993, 261, 1404. (d) Ostovic, D.; Bruice, T. C. Acc. Chem. Res. 1992, 25, 314 and references therein. (2) (a) Mansuy, D.; Battioni, P.; Battioni, J.-P. Eur. J. Biochem. 1989, 184, 267. (b) Holm, R. H. Chem. ReV. 1987, 87, 1401 and references therein. (c) Srinivasan, K.; Michaud, P.; Kochi, J. K. J. Am. Chem. Soc. 1986, 108, 2309. (3) (a) Johnson, R. A.; Sharpless, K. B. In Catalytic Asymmetric Synthesis; Ojima, I., Ed.; VCH: New York, 1993; p 103. (b) Jacobsen, E. N. In Catalytic Asymmetric Synthesis; Ojima, I., Ed.; VCH: New York, 1993; p 159. (c) Jorgensen, K. A. Chem. ReV. 1989, 89, 431. (4) For metal-catalyzed aziridination with PhIdNTs, see: (a) Evans, D. A.; Faul, M. M.; Bilodeau, M. T. J. Am. Chem. Soc. 1994, 116, 2742 and references therein. (b) Li, Z.; Quan, R.; Jacobsen, E. N. J. Am. Chem. Soc. 1995, 117, 5889 and references therein. (c) Noda, K.; Hosoya, N.; Irie, R.; Ito, Y.; Katsuki, T. Synlett 1993, 469. (d) O’Connor, K.; J.; Wey, S.-J.; Burrows, C. J. Tetrahedron Lett. 1992, 33, 1001. (5) For a review on available aziridination and amination methods, see: Kemp, J. E. G. In ComprehensiVe Organic Synthesis; Ley, S. V., Ed.; Pergamon: Oxford, U.K., 1991; Vol. 7, p, 469. See also: Vedejs, E.; Sano, H. Tetrahedron Lett. 1992, 33, 3261. (6) For a review of nitrido metal complexes, see: (a) Dehnicke, K.; Strahle, J. Angew. Chem., Int. Ed. Engl. 1992, 31, 955. (b) Nugent, W. A.; Haymore, B. L. Coord. Chem. ReV. 1980, 31, 123. See also: Nugent, W. A.; Mayer, J. M. Metal-Ligand Multiple Bonds; Wiley-Interscience: New York, 1988. (7) Salen ) N,N′-ethylenebis(salicylideneaminato); saltmen ) N,N′(1,1,2,2-tetramethylethylene)bis(salicylideneaminato). (8) (a) Groves, J. T.; Takahashi, T. J. Am. Chem. Soc. 1983, 105, 2074. (b) Groves, J. T.; Takahashi, T.; Butler, W. M. Inorg. Chem. 1983, 22, 884.
0002-7863/96/1518-0915$12.00/0
(λ g 290 nm) of the corresponding [porphyrinato]Mn(III) azide. Isolation of nitrido-Mn(V) adduct and subsequent treatment of a solution of this complex with cyclooctene (11 equiv) and TFAA (1.2 equiv) afforded the N-trifluoroacetylated aziridine product. Following this example, we have prepared the nitridoMn(V) species (1) derived from (salen)MnN3. The choice of salen as a ligand followed from the work of Arshankow and Poznjak, who had previously prepared (salen)CrVN‚H2O by photolysis of the (salen)CrIIIN3‚2H2O complex.9,10 Although formation of (salen)MnVN (1) was possible by the ArshankowPoznjak protocol, isolated yields of the desired manganese nitride were low (
