Even though the first reports of enantioselective organocatalysis by Wiechert et al. and Hajos and Parrish appeared almost three decades ago, [1] the field of asymmetric catalysis has been dominated by metal catalysis. It is only recently that asymmetric organocatalysis has received renewed attention and become the focus of intense research efforts. [2] This is primarily due to the operational simplicity, the cheap catalysts, and the obvious industrial applications.
Recently, a number of reports on organocatalytic transformations has appeared covering a wide range of reactions including Diels±Alder reactions, [3] aldol reactions, [4] Mannich Experimental Section DBEDOT was obtained according to ref. [14] with 76 % yield: m.p. 96 8C; 1 H NMR (500 MHz, CDCl 3 , 258C, TMS): d = 4.27 ppm (s, 4 H); 13 C NMR (125 MHz, CDCl 3 , 258C, TMS): d = 139.6, 85.4, 64.9 ppm; CP-MAS 13 C NMR (75 MHz, solid state, 25 8C, TMS): d = 140.3, 84.6, 65.1 ppm; MS (70 eV): m/z (%): 302 (55) [M + ], 300 (100), 298 (55); elemental analysis: found: C 23.79, H 1.28, Br 53.00, S 10.86; calcd for C 6 H 4 Br 2 O 2 S: C 24.02, H 1.34, Br 53.27, S 10.69. PEDOT: In a typical experiment, DBEDOT (0.01±2 g) was incubated at 60 8C for 24 h and dried in vacuum (0.1 mbar) at room temperature to give black crystals of bromine-doped PEDOT; elemental analysis: found: C 28.87, H 1.65, Br 38.42, S 12.90; calcd for C 6 H 4 Br 1.2 O 2 S(H 2 O) 0.6 : C 28.01, H 3.50, Br 38.73, S 12.45. The well-ground material was additionally dried in vacuum (0.1 mbar) at 150 8C overnight, then stirred with hydrazine hydrate (50 % aqueous solution, in MeCN) overnight, filtered, and washed with neat MeCN. Vacuum drying afforded a nearly fully dedoped PEDOT; elemental analysis: found: C 46.84, H 2.42, N ~2, Br 0.42, S 19.04; calcd for C 6 H 4 O 2 Br 0.01 S(NH 2 NH 2 ¥3 H 2 O) 0.12 : C 47.63, H 3.44, N 2.22, Br 0.53, S 21.19. CP-MAS 13 C NMR (75 MHz, solid state, 25 8C, TMS): d c = 136.5