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. Author manuscript; available in PMC: 2015 Jan 1.
Published in final edited form as: RSC Adv. 2014 Oct 10;4(96):54051–54059. doi: 10.1039/C4RA10749G

Table 1.

Effect of co-solvent/additive on the enantioselectivity and yield of Michael addition a

Trial Co-solvent/additive ee (%) HPLC yield
(%)		 Binding
constant
Kb/104 (M−1)
1 MOPS buffer, no DNA 10.3 (−) 7
2 MOPS buffer, DNA not sonicated 99.8 (−) 74 2.02
3 MOPS buffer, DNA sonicated 5 min >99 (−) 87 7.15
4 MOPS, r.t., 24 h 95.9 (−) 77
5 MOPS, r.t., 48 h 96.5 (−) 99
6 MOPS, r.t., 72 h 93.8 (−) 96
7 0.2 M acetonitrile 98.0 (−) 69 7.91
8 0.5 M acetonitrile >99 (−) 50 1.23
9 10% acetonitrile (1.9 M) 98.3 (−) 58 0.42
10 25% acetonitrile (4.7 M) 93.0 (−) 36 0.69
11 10% methanol (2.3 M) 71.5 (−) 61 1.13
Ionic liquids as co-solvents
12 0.2 M [BMIM]Cl 93.7 (−) 89 0.64
13 0.2 M [BMIM][CF3COO] 95.4 (−) 93 3.87
14 0.2 M [BMIM][CF3COO], r.t., 24 h 85.7 (−) 85
15 0.5 M [BMIM][CF3COO] 53.1 (−) 36 0.28
16 0.2 M [EMIM][OAc] 25.2 (−) 1.2 1.57
17 0.2 M [BMIM][OAc] 75.5 (−) 3.3 0.39
18 0.2 M [HMIM][OAc] 91.0 (−) 1.9 2.20
19 0.2 M [CH3(OCH2CH2)3-2-Me-Et-Im]
[OAc]		 67.7 (−) 4.6 1.46
20 0.2 M [Choline][OAc] 61.5 (−) 15 1.90
21 0.2 M [BMIM][OTf] 35.3 (−) 0.55 2.12
22 0.2 M [BMIM][BF4] 90.0 (−) 74 8.88
23 0.2 M [BMIM][NO3] 10.0 (−) 25 1.42
24 0.2 M [BMIM][SCN] 69.9 (−) 0.18 0.46
25 0.2 M [BMIM][dca] 90.7 (−) 0.55 0.33
26 0.2 M [Choline][H2PO4] 18.4 (−) 1.6 4.13
27 0.2 M [Choline][bitartrate] 25.2 (−) 0.16 1.11
28 0.5 M [Choline][Tf2N] 8.7 (−) 56
29 0.2 M [BMIM][Tf2N] 23.4 (−) 85
30 0.2 M [CH3(OCH2CH2)3-Et-Im][Tf2N] 2.1 (+) 58 0.95
31 0.5 M [CH3(OCH2CH2)3-Et3N][Tf2N] 11.0 (+) 30 0.71
Inorganic salts as additives
32 0.2 M LiCl 81.5 (−) 6 0.39
32 0.2 M NaCl 63.6 (−) 43 0.73
33 0.2 M KCl 62.4 (−) 52 1.26
34 0.2 M Na[CF3COO] 55.9 (−) 73 2.43
35 0.2 M NaOAc 26.2 (−) 8 4.32
36 0.2 M Na[OTf] 47.2 (−) 59 1.64
37 0.2 M BaBF4 62.6 (−) 14 2.19
38 0.2 M NaNO3 87.6 (−) 51 0.73
39 0.2 M NaSCN 26.5 (−) 2 0.44
40 0.2 M Na[dca] 68.1 (−) 1 1.06
41 0.2 M Li[Tf2N] 4.9 (−) 28 1.95
42 0.2 M urea 98.1 (−) 71 4.24
DES and related compounds as co-solvents
43 0.2 M Choline chloride/glycerol (1:2) 92.4 (−) 90 1.14
44 0.5 M Choline chloride/glycerol (1:2) 58.6 (−) 53 0.39
45 0.2 M Choline chloride/glycerol (1:2), r.t., 24 h 94.0 (−) 88
46 0.2 M Choline chloride/glycerol (1:2), r. t., 48 h 86.9 (−) 95
47 0.2 M Choline chloride/glycerol (1:2), r.t., 3 days 87.1 (−) 97
48 0.2 M Choline acetate/glycerol (1:1.5) 71.8 (−) 16 4.10
49 0.5 M Choline acetate/glycerol (1:1.5) 16.1 (−) 3.5 4.01
50 0.2 M Choline chloride 92.8 (−) 80 1.90
51 0.5 M Choline chloride 59.6 (−) 38 1.27
52 0.2 M Choline chloride, r.t., 24 h 71.1 (−) 29
53 0.2 M Glycerol 98.4 (−) 65 0.80
54 0.4 M Glycerol >99 (−) 96 8.15
55 0.8 M Glycerol >99 (−) 63 0.67
56 0.4 M Glycerol, r.t, 24 h 96.2 (−) 83
Glymes and glycols as co-solvents
57 0.5 M monoglyme >99 (−) 73 13.06
58 0.5 M diglyme >99 (−) 56 1.91
59 0.5 M triglyme >99 (−) 75 3.45
60 0.2 M tetraglyme 99.8 (−) 87 12.08
61 0.5 M tetraglyme >99 (−) 76 3.87
62 0.2 M tetraglyme, r.t., 24 h 96.3 (−) 78
63 0.5 M dipropylene glycol dimethyl ether >99 (−) 49 2.77
64 0.5 M dipropylene glycol dimethyl ether, r.t., 24 h >99 (−) 87
65 0.2 M ethylene glycol 98.3 (−) 79 0.94
66 0.2 M diethylene glycol 99.3 (−) 59 2.36
67 0.2 M triethylene glycol 97.8 (−) 61 8.59
68 0.4 M tetraethylene glycol 99.8 (−) 71 20.51

Note

a

reaction conditions (except noted otherwise): 10 mg DNA (Sigma D1626) in 5.0 mL MOPS buffer sonicated for 5 min in ice bath, 15 µmol acyl donor (1a), 100 eq. dimethylmalonate, 0.15 mM [Cu(dmbipy)(NO3)2], 30 mM pH 6.5 MOPS, reaction volume 15.0 mL, 5 °C for 3 days (except noted otherwise); bold values of yields and ees indicate they are relatively high.