6
A. Hussain, D. Mukherjee / Tetrahedron xxx (2014) 1e7
61.1, 57.7, 20.6, 20.5, 20.5, ESI MS (m/z): 342 [M]þ. Anal. Calcd for
12H16Cl2O7: C, 42.00; H, 4.70. Found C, 41.87; H, 4.59.
yield); Rf (20% EtOAc/hexane) 0.6; ½a D25
ꢂ
þ154 (c 1.0, CHCl3); IR
C
(CHCl3) 1744, 772 cmꢁ1 1H NMR (400 MHz, CDCl3)
; d 6.21 (d,
J¼3.6 Hz, 1H), 5.50 (d, J¼3.0 Hz, 1H), 5.38 (dd, J¼11.1, 3.2 Hz, 1H),
4.61 (t, J¼6.4 Hz, 1H), 4.44 (dd, J¼11.0, 3.6 Hz, 1H), 4.18e4.06 (m,
4.5. Preparation and spectral data of 3,4,6-tri-O-benzoyl-2-
chloro-2-deoxy- -mannopyranosyl chloride (4c)
a
2H), 2.15 (s, 3H), 2.06 (s, 6H); 13C NMR (125 MHz, CDCl3)
d 170.4,
169.8, 169.6, 93.6, 69.8, 69.2, 67.5, 60.9, 55.4, 20.7, 20.6, 20.5, ESI MS
(m/z): 342 [M]þ. Anal. Calcd for C12H16Cl2O7: C, 42.00; H, 4.70.
Found C, 41.92; H, 4.67.
Prepared by the general procedure for dichlorination of glycals
by using 1c (100 mg, 0.22 mmol), NCS (88 mg, 3 equiv), and PPh3
(86 mg, 1.5 equiv) to yield the desired product 4c as semisolid (90%
yield); Rf (10% EtOAc/hexane) 0.5; ½a D25
ꢂ
þ2.7 (c 1.0, CHCl3); IR
4.9. Preparation and spectral data of 3,4,6-tri-O-benzoyl-2-
chloro-2-deoxy-a-galactopyranosyl chloride (2g)
(CHCl3) 1727, 1601, 771 cmꢁ1; 1H NMR (125 MHz, CDCl3)
d
8.10 (dd,
J¼16.3, 8.0 Hz, 3H), 7.99 (dd, J¼9.6, 8.6 Hz, 4H), 7.58e7.51 (m, 2H),
7.44 (m, 3H), 7.41e7.37 (m, 4H), 6.30 (d, 1H), 6.15 (t, J¼9.9 Hz, 1H),
6.06 (dd, J¼10.1, 3.4 Hz, 1H), 4.89 (d, J¼3.4 Hz, 1H), 4.70e4.64 (m,
Prepared by the general procedure for dichlorination of glycals by
using 1g (100 mg, 0.22 mmol), NCS (88 mg, 3 equiv.), and PPh3
(86 mg, 1.5 equiv) to yield the desired product 2g as semisolid (88%
2H), 4.48 (dd, J¼12.1, 3.7 Hz,1H); 13C NMR (125 MHz, CDCl3)
d 165.9,
165.3, 164.9, 133.5, 133.5, 133.4, 132.9, 129.9, 129.7, 129.6, 129.5,
129.2, 129.1, 128.4, 128.4, 128.3, 128.3, 128.3, 128.2, 128.2, 128.2,
90.9, 71.8, 69.0, 65.1, 61.9, 59.9, ESI MS (m/z): 528 [M]þ. Anal. Calcd
for C27H22Cl2O7: C, 61.26; H, 4.19. Found C, 61.22; H, 4.15.
yield); Rf (10% EtOAc/hexane) 0.5; ½a D25
ꢂ
þ80.3 (c 1.0, CHCl3); IR
(CHCl3) 1728, 1601, 772 cmꢁ1; 1H NMR (400 MHz, CDCl3)
d
8.02e7.98
(m, 4H), 7.90e7.86 (m, 2H), 7.56e7.39 (m, 7H), 7.32 (d, J¼7.8 Hz, 2H),
6.39 (d, J¼3.6 Hz, 1H), 6.05 (d, J¼2.1 Hz, 1H), 5.82 (dd, J¼11.0, 3.2 Hz,
1H), 4.97 (t, J¼6.5 Hz, 1H), 4.76 (dd, J¼11.0, 3.6 Hz, 1H), 4.61 (dd,
J¼11.5, 6.8 Hz, 1H), 4.40 (dd, J¼11.5, 6.1 Hz, 1H); 13C NMR (125 MHz,
4.6. Preparation and spectral data of compounds 2d and 4d
CDCl3)
d 165.9, 165.2, 165.2, 133.8, 133.4, 133.5, 130.3, 129.9, 129.9,
Prepared by the general procedure for dichlorination of glycals
by using 1d (100 mg, 0.30 mmol), NCS (121 mg, 3 equiv.), and PPh3
(119 mg, 1.5 equiv) to yield the a-gluco/a-manno mixture (2d/4d in
129.9, 129.8, 129.8, 129.2, 128.9, 128.8, 128.7, 128.6, 128.5, 128.5, 128.4,
127.8, 93.8, 70.4, 69.9, 68.5, 61.7, 56.1, ESI MS (m/z): 528 [M]þ. Anal.
Calcd for C27H22Cl2O7: C, 61.26; H, 4.19. Found C, 61.19; H, 4.11.
the ratio of 1:0.32) as semisolid (90% yield).
4.10. 3,4-Di-O-acetyl-2-chloro-2,6-dideoxy-a-glucopyranosyl
4.6.1. 2,3,4,6-Tetra-O-acetyl-2-chloro-2-deoxy-
a
-glucopyranosyl
chloride (2h)
chloride (2d). Rf (30% EtOAc/hexane) 0.5; IR (CHCl3) 1744,
771 cmꢁ1 1H NMR (400 MHz, CDCl3)
;
d
6.20 (s, 1H), 5.97 (d,
Prepared by the general procedure for dichlorination of glycals
by using 1h (100 mg, 0.47 mmol), NCS (187 mg, 3 equiv.), and PPh3
(185 mg, 1.5 equiv) to yield the desired product 2h as white solid
J¼8.8 Hz, 1H), 5.10e5.07 (m, 1H), 4.41 (dt, J¼8.3, 5.4 Hz, 2H), 4.23
(dd, J¼9.5, 4.7 Hz, 1H), 2.18 (s, 3H), 2.12 (s, 3H), 2.09 (s, 3H), 2.06 (s,
3H); 13C NMR (125 MHz, CDCl3)
d
170.5, 169.2, 169.1, 168.8, 108.7,
(88% yield); mp135e136 ꢀC, Rf (10% EtOAc/hexane) 0.6; ½a D25
ꢂ
71.9, 71.9, 65.3, 61.6, 20.7, 20.7, 20.6, 20.5, ESI MS (m/z): 400 [M]þ.
ꢁ214 (c 1.0, CHCl3); IR (CHCl3) 1728, 772 cmꢁ1; 1H NMR (400 MHz,
CDCl3)
d
6.09 (d, J¼3.7 Hz, 1H), 5.47 (dd, J¼10.4, 9.5 Hz, 1H), 4.83 (t,
4.6.2. 2,3,4,6-Tetra-O-acetyl-2-chloro-2-deoxy-
chloride (4d). Rf (30% EtOAc/hexane) 0.5; IR (CHCl3) 1744,
771 cmꢁ1 1H NMR (400 MHz, CDCl3)
6.33 (s, 1H), 5.74 (d,
a
-mannopyranosyl
J¼9.7 Hz, 1H), 4.31 (dq, J¼10.1, 6.2 Hz, 1H), 4.14 (dd, J¼10.5, 3.7 Hz,
1H), 2.07 (d, J¼7.8 Hz, 6H), 1.25 (d, J¼6.2 Hz, 3H); 13C NMR
;
d
(125 MHz, CDCl3) d 169.8, 169.78, 92.7, 73.6, 71.4, 68.9, 58.2, 20.7,
J¼9.0 Hz, 1H), 5.12e5.10 (m, 1H), 4.41 (dt, J¼8.3, 5.4 Hz, 2H), 4.23
20.6, 17.1, ESI MS (m/z): 242 [M]þ. Anal. Calcd for C8H12Cl2O4: C,
(dd, J¼9.5, 4.7 Hz, 1H), 2.18 (s, 3H), 2.16 (s, 3H), 2.11 (s, 3H), 2.09 (s,
39.53; H, 4.98. Found C, 39.49; H, 4.4.93.
3H); 13C NMR (125 MHz, CDCl3)
d 170.4, 169.3, 169.2, 168.8, 107.9,
72.7, 72.1, 65.0, 61.5, 20.7, 20.6, 20.5, 20.4, ESI MS (m/z): 400 [M]þ.
4.11. 3,4-Bis(benzyloxy)-2-((benzyloxy)methyl)-5-chloro-3,4-
dihydro-2H-pyran (6)
4.7. Preparation and spectral data of 3,4,6-tri-O-benzyl-2-
chloro-2-deoxy-
a
-galactopyranosyl chloride (2e)
To a solution of 1,2-dichloropyranoside 2a/4a mixture (200 mg,
0.41 mmol) in diethyl ether (3 mL) was added KOt-Bu (92 mg,
2 equiv). The reaction mixture was allowed to stir for 3 h. Completion
of reaction was checked by TLC. The reaction mixture was extracted
with ethyl acetate, dried over Na2SO4, and concentrated. The residue
was purified by 60e120 silica gel column chromatography (EtOAc/
hexane) to yield the product 6 (85%) as white solid. M.p 30e35 ꢀC; Rf
(20% EtOAc/hexane) 0.55; IR (CHCl3) 3064, 3031, 2906, 2867, 1649,
Prepared by the general procedure for dichlorination of glycals
by using 1e (100 mg, 0.24 mmol), NCS (96 mg, 3 equiv), and PPh3
(94 mg, 1.5 equiv) to yield a-gluco isomer (2e) as semisolid (89%
yield); Rf (10% EtOAc/hexane) 0.6; ½a D25
ꢂ
þ10 (c 1.0, CHCl3); IR (CHCl3)
1618, 1113, 771 cmꢁ1 1H NMR (400 MHz, CDCl3)
; d 7.43e7.25 (m,
15H), 6.18 (d, J¼3.5 Hz, 1H), 4.91 (d, J¼11.1 Hz, 1H), 4.80 (d,
J¼11.4 Hz, 1H), 4.73 (d, J¼11.4 Hz, 1H), 4.64 (dd, J¼10.5, 3.5 Hz, 1H),
4.54e4.41 (m, 3H), 4.32 (t, J¼6.5 Hz, 1H), 4.01 (s, 1H), 3.94 (dd,
J¼10.5, 2.6 Hz, 1H), 3.61e3.52 (m, 2H); 13C NMR (125 MHz, CDCl3)
1496, 1454, 1364, 698 cmꢁ1 1H NMR (400 MHz, CDCl3)
; d 7.41e7.18
(m, 15H), 6.64 (s, 1H), 4.60 (m, 6H), 4.27 (dd, J¼10.1, 5.2 Hz, 1H), 4.10
(d, J¼4.3 Hz, 1H), 3.95 (dd, J¼5.5, 4.4 Hz, 1H), 3.79 (dd, J¼10.7, 6.1 Hz,
d
137.9, 137.6, 128.7, 128.7, 128.6, 128.5, 128.5, 128.4, 128.3, 128.3,
1H), 3.66 (dd, J¼10.7, 4.2 Hz, 1H); 13C NMR (125 MHz, CDCl3)
d 142.5,
128.2, 128.1, 128.0, 127.9, 127.9, 127.9, 127.9, 127.7, 95.6, 78.4, 75.3,
74.5, 73.6, 73.6, 72.9, 67.8, 58.8; ESI MS (m/z): 486 [M]þ. Anal. Calcd
for C27H28Cl2O4: C, 66.53; H, 5.79. Found C, 66.45; H, 5.69.
137.9, 137.8, 137.6, 128.6, 128.5, 128.0, 127.9, 127.8, 110.0, 76.5, 76.4,
73.8, 73.5, 72.8, 72.5, 67.8; ESI MS (m/z): 450 [M]þ. Anal. Calcd for
C27H27ClO4: C, 71.91; H, 6.03. Found C, 71.83; H, 6.00.
4.8. Preparation and spectral data of 3,4,6-tri-O-acetyl-2-
4.12. 3,4-Bis(benzyloxy)-2-((benzyloxy)methyl)-3,4-dihydro-
chloro-2-deoxy-
a
-glalactopyranosyl chloride (2f)
5-phenyl-2H-pyran (8)
Prepared by the general procedure for dichlorination of glycals
by using 1f (100 mg, 0.37 mmol), NCS (147 mg, 3 equiv.), and PPh3
(145 mg, 1.5 equiv) to yield the desired product 2f as semisolid (89%
The compound 6 (100 mg, 0.22 mmol) was dissolved in toluene
(3 mL) phenylboronic acid 7 (27 mg, 1 equiv) was added to it fol-
lowed by the addition of Cs2CO3 (101 mg, 1.4 equiv) and SPhos