C O M M U N I C A T I O N S
initially have no bromine terminal groups and therefore no azide-
initiating sites).
In conclusion, tailor-made linear macromolecules synthesized by
ATRP appear to be robust and versatile supports for the synthesis
of sequence-ordered oligomers. Indeed, these macromolecular
supports can be used not only for the conventional synthesis and
cleavage of defined oligomers but also for the preparation of
advanced macromolecular architectures containing sequence-defined
segments.
Acknowledgment. The Fraunhofer Society and the Federal
Ministry of Education and Research are acknowledged for financial
support. Additionally, J.-F.L. thanks Professor Andre´ Laschewsky
(Universita¨t Potsdam) for fruitful discussions.
Supporting Information Available: Full experimental section and
Figures S1-S7. This material is available free of charge via the Internet
References
(1) Badi, N.; Lutz, J.-F. Chem. Soc. ReV., in press.
(2) (a) Storhoff, J. J.; Mirkin, C. A. Chem. ReV. 1999, 99, 1849–1862. (b) van
Hest, J. C. M.; Tirrell, D. A. Chem. Commun. 2001, 1897–1904. (c) Becker,
M. L.; Liu, J.; Wooley, K. L. Chem. Commun. 2003, 180–181.
(3) (a) Alemdaroglu, F. E.; Herrmann, A. Org. Biomol. Chem. 2007, 5, 1311–
1320. (b) Bo¨rner, H. G.; Schlaad, H. Soft Matter 2007, 394–408.
(4) Merrifield, R. B. J. Am. Chem. Soc. 1963, 85, 2149–2154.
(5) Lutz, J.-F.; Bo¨rner, H. G. Prog. Polym. Sci. 2008, 33, 1–39.
(6) Dickerson, T. J.; Reed, N. N.; Janda, K. D. Chem. ReV. 2002, 102, 3325–
3344.
(7) (a) Shemyakin, M. M.; Ovchinnikov, Y. A.; Kinyushkin, A. A.; Kozhevni-
kova, I. V. Tetrahedron Lett. 1965, 6, 2323–2327. (b) Hayatsu, H.; Khorana,
H. G. J. Am. Chem. Soc. 1966, 88, 3182–3183. (c) Bayer, E.; Mutter, M.
Nature 1972, 237, 512–513.
(8) (a) Wang, J.-S.; Matyjaszewski, K. J. Am. Chem. Soc. 1995, 117, 5614–
5615. (b) Chiefari, J.; Chong, Y. K.; Ercole, F.; Krstina, J.; Jeffery, J.; Le,
T. P. T.; Mayadunne, R. T. A.; Meijs, G. F.; Moad, C. L.; Moad, G.;
Rizzardo, E.; Thang, S. H. Macromolecules 1998, 31, 5559–5562. (c)
Benoit, D.; Chaplinski, V.; Braslau, R.; Hawker, C. J. J. Am. Chem. Soc.
1999, 121, 3904–3920.
Figure 3. Oligomer synthesis on a cleavable soluble polystyrene support
(Figure 1, approach b). H NMR spectra recorded in CDCl3 for (top) the
formed polystyrene-b-oligomer copolymers before TFA/CH2Cl2 cleavage,
(middle) the polystyrene support after cleavage and filtration, and (bottom)
the formed oligomer after cleavage and isolation.
1
(9) (a) Du, J.; Armes, S. P. J. Am. Chem. Soc. 2005, 127, 12800–12801. (b)
Mantovani, G.; Lecolley, F.; Tao, L.; Haddleton, D. M.; Clerx, J.;
Cornelissen, J. J. L. M.; Velonia, K. J. Am. Chem. Soc. 2005, 127, 2966–
2973. (c) Korth, B. D.; Keng, P.; Shim, I.; Bowles, S. E.; Tang, C.;
Kowalewski, T.; Nebesny, K. W.; Pyun, J. J. Am. Chem. Soc. 2006, 128,
6562–6563. (d) Lutz, J.-F.; Akdemir, O.; Hoth, A. J. Am. Chem. Soc. 2006,
128, 13046–13047. (e) Pfeifer, S.; Lutz, J.-F. J. Am. Chem. Soc. 2007,
129, 9542–9543. (f) De, P.; Li, M.; Gondi, S. R.; Sumerlin, B. S. J. Am.
Chem. Soc. 2008, 130, 11288–11289.
oligomers (approach c in Figure 1). In this case, the bromine ω-end
groups of the ATRP polystyrene chains (Mn ≈ 3900 g mol-1, Mw/
Mn ≈ 1.13) were first transformed into azide moieties by nucleo-
philic substitution with sodium azide.15 These functional chain ends
were then used as initiating sites. Six alternating growth steps were
performed on the soluble polystyrene support (three amidifications
and three cycloadditions). As for the previous approach, the
(10) Gravert, D. J.; Datta, A.; Wentworth, P.; Janda, K. D. J. Am. Chem. Soc.
1998, 120, 9481–9495.
(11) (a) Rostovtsev, V. V.; Green, L. G.; Fokin, V. V.; Sharpless, K. B. Angew.
Chem., Int. Ed. 2002, 41, 2596–2599. (b) Hawker, C. J.; Wooley, K. L.
Science 2005, 309, 1200–1205. (c) Lutz, J.-F. Angew. Chem., Int. Ed. 2007,
46, 1018–1025.
(12) Malkoch, M.; Thibault, R. J.; Drockenmuller, E.; Messerschmidt, M.; Voit,
B.; Russell, T. P.; Hawker, C. J. J. Am. Chem. Soc. 2005, 127, 14942–
14949.
(13) Harju, K.; Vahermo, M.; Mutikainen, I.; Yli-Kauhaluoma, J. J. Comb. Chem.
2003, 5, 826–833.
1
sequential growth of the oligomer was monitored by H NMR
spectroscopy. This technique evidenced high reaction yields in each
step. After synthesis, the 1H NMR spectra and SEC data indicated
the formation of a well-defined diblock copolymer containing a
sequence-ordered segment with a molecular weight of ∼1000 g
mol-1 (Figures S6 and S7 in the Supporting Information). Contrary
to what occurred with approach b, no triblock copolymers were
formed in the present case. Indeed, approach c relies on ω-chain
end initiation, in which dead chains are simply inactive (i.e., they
(14) Wang, S.-S. J. Am. Chem. Soc. 1973, 95, 1328–1333.
(15) Lutz, J.-F.; Bo¨rner, H. G.; Weichenhan, K. Macromol. Rapid Commun.
2005, 26, 514–518.
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