Alysts [7,20]. When ten mol of polysulfate catalyst rather of 20 mol , the

Alysts [7,20]. When ten mol of polysulfate catalyst rather of 20 mol , the yield dropped even when the reaction time was prolonged (entry was 7a was employed instead of 20 mol , the yield dropped even when the reaction time 13). When the reaction was performed at 0 , the enantioselectivity increased to 94 ee, prolonged (entry 13). When the reaction was performed at 0 C, the enantioselectivity although the reaction took a a great deal longer time (48 h) to give an acceptable yield (80 ) (entry enhanced to 94 ee, although the reaction took a substantially longer time (48 h) to offer an acceptable 14). When several acid cocatalysts for instance trifluoroacetic acid (TFA), ptoluenesulfonic yield (80 ) (entry 14). When a variety of acid cocatalysts which Dicloxacillin (sodium) supplier include trifluoroacetic acid (TFA), acid (pTsOH), HCl, HClO4, Azamethiphos Inhibitor methanesulfonic acid (MsOH), and HBF4 have been examined, the ptoluenesulfonic acid (pTsOH), HCl, HClO4 , methanesulfonic acid (MsOH), and HBF4 yields and both the diastereo and enantioselectivities of your asymmetric reactions remain were examined, the yields and both the diastereo and enantioselectivities in the asymmetric just about related (entries 82). Thus, we chose DMF:H2O (95:5 (v/v)) with 20 mol in the reactions stay practically similar (entries 82). Therefore, we chose DMF:H2 O (95:5 (v/v)) with polymeric MacMillan catalyst and 22 mol of the TFA cocatalyst at space temperature as 20 mol on the polymeric MacMillan catalyst and 22 mol in the TFA cocatalyst at room the optimized DA reaction situations (entry 7). temperature because the optimized DA reaction situations (entry 7).a TableTable 4. Optimization of reaction situations for the asymmetric Diels lder reaction . four. Optimization of reaction situations for the asymmetric Diels lder reaction a .Entryc b Yield endo Yield Time 11 c exo/endo11 exo ee exo d endo ee d Acid b (h) exo/endo ee d ee d 1 H2 O TFA 24 trace n.d. n.d. n.d. 1 TFA 57 24 trace n.d. n.d. 2 MeOH:H2 O (95:five) TFA H2O 24 46/53 n.d. 63 59 three Toluene:H2 O (95:five) TFA 24 57/43 46/53 7363 two MeOH:H2O (95:5) TFA 46 24 57 59 64 four DCM:H2 O (95:5) TFA 24 53/47 57/43 8073 three Toluene:H2O (95:5) TFA 69 24 46 64 79 5 ACN:H2 O (95:5) TFA 24 79 60/40 89 91 four DCM:H2O (95:5) TFA 24 69 53/47 80 79 6 THF:H2 O (95:five) TFA 24 88 54/46 91 94 5 ACN:H2O (95:5) TFA 92 24 79 91 93 7 DMF:H2 O (95:5) TFA 24 51/49 60/40 9289 6 THF:H TFA 85 24 88 94 91 eight DMF:H2 O (95:five) pTsOH 2O (95:5) 24 55/45 54/46 9191 9 DMF:H2 O (95:5) HCl 2O (95:five) 24 92 56/44 51/49 9092 TFA 24 92 93 89 7 DMF:H ten DMF:H2 O (95:five) HClO4 2O (95:five) 24 82 52/48 55/45 8991 eight DMF:H pTsOH 24 85 91 88 11 DMF:H2 O (95:five) MsOH 24 84 53/47 88 91 9 DMF:H2O (95:5) HCl 79 24 92 89 89 12 DMF:H2 O (95:5) HBF4 24 56/44 56/44 9190 10 DMF:H2O (95:five) HClO4 24 82 88 92 13 e DMF:H2 O (95:5) TFA 24 62 53/47 52/48 9289 DMF:H2 O (95:5) TFA 48 80 51/49 53/47 9488 14 f 11 DMF:H2O (95:five) MsOH 24 84 91 94 a Reaction conditions: 0.050 mmol (49 mg, 20 mol ) on the polysulfate catalyst 7a, 0.055 mmol (22 mol ) on the acid cocatalyst, 0.25 mmol 12 DMF:H2O (95:five) HBF4 24 79 56/44 91 89 (31 , 1 equiv.) of (E)cinnamaldehyde, and 1.25 mmol (0.11 mL,TFA five equivalent) of cyclopentadiene at area temperature in 0.50 mL of 13 e DMF:H2O (95:5) 24 62 53/47 92 92 solvent. b Yield of isolated item. c Determined by 1 H NMR spectroscopy. d Determined by HPLC having a chiral OJH column immediately after 14 f DMF:H2O (95:five) reaction was performed with 80 TFA 48.