Epoxidation of Electrophilic Olefins
FULL PAPER
3,4-Di-O-benzyl-2-deoxy-a-d-lyxo-
hexopyranosyl hydroperoxide (9):
Yield: 0.35 g, 80%; solid; m.p. 89–
928C;
[a]2D0 =+62.7
(c=0.6
in
CHCl3); 1H NMR (500 MHz, CDCl3):
d=9.84 (brs, 1H; OOH), 5.43 (d,
1H,
J1,2a =4.7 Hz; H-1), 4.93, 4.62
(2d, 2H, J=11.7 Hz; PhCH2O), 4.60,
4.56 (2d, 2H, J=12.0 Hz; PhCH2O),
3.92–3.84 (m, 2H; H-6a, H-5), 3.76
(brs, 1H; H-4), 3.73 (ddd, 1H, J3,2a
12.3, 3,2b =4.7, 3,4 =2.5 Hz; H-3),
3.54–3.46 (m, 1H; H-6b), 2.32–2.03
(m, 1H; OH), 2.29 (ddd, 1H, J2a,2b
13.4, J2a,3 =12.3, J2a,1 =4.7 Hz; H-2a),
2.06 (dd, 1H, 2b,2a =13.4, J2b,3
=
J
J
=
J
=
4.7 Hz; H-2b); 13C NMR (125 MHz,
CDCl3): d=102.18 (C-1), 74.11 (C-4),
74.10 (PHCH2O), 72.81 (C-3), 72.10
(C-5), 70.61 (PHCH2O), 63.51 (C-6),
28.24 ppm (C-2); 1H NMR (500 MHz,
C6D6): d=10.88 (brs, 1H; OOH),
5.47 (d, 1H, J1,2a =4.7 Hz; H-1), 4.88,
4.43 (2d, 2H, J=11.5 Hz; PhCH2O),
4.27, 4.22 (2d, 2H, J=11.9 Hz;
PhCH2O), 4.00 (dd, 1H, J6a,6b =11.2,
J
6a,5 =8.3 Hz; H-6a), 3.89 (m, 1H; H-
5), 3.62 (ddd, 1H, J3,2a =12.5, J3,2b
4.7, J3,4 =2.5 Hz; H-3), 3.45 (dd, 1H,
6b,6a =11.2, J6b,5 =3.2 Hz; H-6b), 3.42
(brs, 1H; H-4), 2.24 (ddd, 1H, J2a,2b
=
J
=
13.3, J2a,3 =12.5, J2a,1 =4.7 Hz; H-2a),
1.92 (ddd, 1H, J2b,2a =13.3, J2b,3 =4.7,
J
2b,1 =1.2 Hz;
H-2b);
13C NMR
Figure 8. Schematic energetic representation [kcalmolÀ1] of the possible reaction pathways observed in differ-
ent potential energy surfaces for sodium and potassium complexes. The calculated relative free energies in-
clude the solvent effects.
(125 MHz, C6D6): d=102.67 (C-1),
74.73 (C-4), 74.44 (PHCH2O), 73.97
(C-3), 72.82 (C-5), 70.51 (PHCH2O),
64.04 (C-6), 28.62 ppm (C-2); IR
(film): n˜ =3325, 1454, 1362, 1112,
MgSO4 and evaporated. The crude product was purified on a silica-gel
1039, 1028, 737, 698 cmÀ1; HRMS (ESI): m/z: calcd for C20H24O6Na:
383.1465; found: 383.1448 [M+Na]+; elemental analysis calcd (%) for
C20H24O6: C 66.65, H 6.71; found: C 66.76, H 6.78.
column by usingdichloromethane/acetone 20:1 v/v as the eluent to
afford the corresponding6- O-carbamoyl glycoside (0.32 g, 83%). Solid;
m.p. 101–1038C; [a]2D0 =+83.0 (c=0.55 in CH2Cl2); 1H NMR (500 MHz,
CDCl3): d=4.96, 4.66 (2d, 2H, J=11.6 Hz; PhCH2O), 4.89 (brd, 1H; H-
1), 4.62, 4.60 (2d, 2H, J=11.9 Hz; PhCH2O), 4.57 (brs, 2H; NH2), 4.19
3,4-Di-O-benzyl-2-deoxy-6-O-carbamoyl-a-d-lyxo-hexopyranosyl hydro-
peroxide (10): Yield: 0.38 g, 79%; solid; m.p. 144–1468C; [a]2D0 =+59.4
(c=0.6 in CH2Cl2); 1H NMR (500 MHz, CDCl3): d=9.62 (s, 1H; OOH),
J1,2a =4.4 Hz; H-1), 4.96, 4.65 (2d, 2H, J=11.5 Hz;
PhCH2O), 4.76 (brs, 2H; NH2), 4.61, 4.57 (2d, 2H, J=12.0 Hz;
PhCH2O), 4.26 (dd, 1H, J6a,6b =11.3, J6a,5 =6.8 Hz; H-6a), 4.13 (dd, 1H,
(dd, 1H, J6a,6b =11.2, J6a,5 =7.0 Hz; H-6a), 4.16 (dd, 1H, J6b,6a =11.2, J6b,5
5.4 Hz; H-6b), 3.89 (ddd, 1H, J3,2a =12.0, J3,2b =4.6, J3,4 =2.5 Hz; H-3),
3.87 (brt, 1H; H-5), 3.82 (brs, 1H; H-4), 3.31 (s, 3H; OCH3), 2.22 (ddd,
=
5.41 (d, 1H,
1H,
J
J2a,2b =12.7, J2a,1 =3.7, J2a,3 =12.0 Hz; H-2a), 2.01 ppm (ddd, 1H,
J
6b,6a =11.3, J6b,5 =5.8 Hz; H-6b), 4.02 (m, 1H; H-5), 3.81 (brs, 1H; H-4),
3.74 (ddd, 1H, J3,2a =12.4, J3,2b =4.6, J3,4 =2.4 Hz; H-3), 2.29 (ddd, 1H,
2b,2a =12.7, J2b,3 =4.6, J2b,1 =1.2 Hz; H-2b); 13C NMR (125 MHz, CDCl3):
d=156.34 (C=O), 98.96 (C-1), 74.79 (C-4), 74.12 (PHCH2O), 72.79 (C-3),
70.55 (PHCH2O), 69.03 (C-5), 64.88 (C-6), 54.77 (OCH3), 30.91 ppm (C-
J
2a,2b =13.4, J2a,3 =12.4, J2a,1 =4.4 Hz; H-2a), 2.04 ppm (dd, 1H, J2b,2a =
13.4, J2b,3 =4.6 Hz; H-2b); 13C NMR (125 MHz, CDCl3): d=156.87 (C=
O), 101.88 (C-1), 74.26 (PHCH2O), 73.95 (C-4), 72.25 (C-3), 70.56
(PHCH2O), 69.70 (C-5), 64.31 (C-6), 28.09 ppm (C-2); 1H NMR
(500 MHz, C6D6): d=9.05 (s, 1H; OOH), 5.44 (brd, 1H, J1,2a =4.4 Hz; H-
2); IR (CH2Cl2): n˜ =3536, 3424, 2927, 1734, 1584, 1352, 1098, 1050 cmÀ1
;
HRMS (ESI): m/z: calcd for C22H27NO6Na: 424.1730 [M+Na]+; found:
424.1750; elemental analysis calcd (%) for C22H27NO6: C 65.82, H 6.78, N
3.49; found: C 65.91, H 6.64, N 3.52.
1), 5.03 (d, 1H; PhCH2O), 4.62 (d, 1H; PhCH2O), 4.26 (dd, 1H, J6a,6b
=
11.1, J6a,5 =6.8 Hz; H-6a), 4.43 (dd, 1H, J6b,6a =11.1, J6b,5 =5.7 Hz; H-6b),
4.33–4.26 (m, 2H; PhCH2O), 4.17 (m, 1H; H-5), 3.87 (brs, 2H; NH2),
Synthesis of hydroperoxides. General procedure: 50% H2O2 (14.4 mL)
and concentrated H2SO4 (0.24 mL) were added to a solution of methyl
glycoside (1.2 mm) in 1,4-dioxane (4.8 mL). The reaction was stirred at
room temperature until disappearance of the substrate was complete
(TLC). Subsequently, the mixture was diluted with CH2Cl2 (100 mL) and
the organic layer was separated. The water layer was extracted with
CH2Cl2 and the combined extracts were washed with water (caution must
be taken; even a small amount of hydrogen peroxide left can cause ex-
plosion duringevaporation of the solvent), dried over Na 2SO4, and
evaporated at room temperature. The crude product was purified on a
silica-gel column by using hexane/ethyl acetate 3:2 v/v as an eluent to
3.70–3.63 (m, 2H; H-4, H-3), 2.33 (ddd, 1H, J2a,2b =13.3, J2a,3 =12.2, J2a,1
=
4.4 Hz; H-2a), 1.93 (dd, 1H, 2b,2a =13.3, 2b,3 =4.6 Hz; H-2b); IR
J
J
(CH2Cl2): n˜ =3532, 3423, 2990, 1735, 1425, 1356, 1111, 1053, 897 cmÀ1
;
HRMS (ESI): m/z: calcd for C21H25NO7Na: 426.1523 [M+Na]+; found:
426.1537; elemental analysis calcd (%) for C21H25NO7: C 62.52, H 6.25, N
3.47; found: C 62.41, H 6.16, N 3.33.
3,4-Di-O-benzyl-2-deoxy-6-O-(N-ethylcarbamoyl)-a-d-lyxo-hexopyrano-
syl hydroperoxide (11): Yield: (0.37 g, 72%); solid; m.p. 112–114 C;
[a]2D0 =+54.9 (c=0.35 in CH2Cl2); 1H NMR (500 MHz, CDCl3): d=8.95
(brs, 1H; OOH), 5.42 (d, 1H, J1,2a =4.7 Hz; H-1), 4.96, 4.66 (2d, 2H, J=
11.5 Hz; PhCH2O), 4.63 (brs, 1H; NH), 4.60, 4.57 (2d, 2H, J=12.0 Hz;
afford the correspondinghydro ACHTERpUNG erACHERToGNU xACHTREiUNG de.
Chem. Eur. J. 2008, 14, 6087 – 6097
ꢀ 2008 Wiley-VCH VerlagGmbH & Co. KGaA, Weinheim
6095