C-Glycosylation Reactions of Pyranoses
chromatography (hexanes to 1:9 Et2O/hexanes) to afford the 1,4-
trans product: 1H NMR (500 MHz, CDCl3) δ 7.41-7.20 (m, 15H),
5.69-5.65 (m, 1H), 5.03-4.99 (m, 3H), 4.84-4.77 (m, 3H), 4.65
(d, J ) 11.5 Hz, 1H and d, J ) 11.6 Hz, 1H), 4.08-4.03 (m, 2H),
3.77-3.75 (d, J ) 2.6 Hz, 1H), 3.57-3.51 (dd, J ) 8.8, 2.8 Hz,
1H), 3.26-3.24 (t, J ) 7.0 Hz, 1H), 3.17-3.12 (t, J ) 12.6 Hz,
1H), 2.44-2.40 (m, 1H), 2.22-2.18 (m, 1H); 13C NMR (125 MHz,
CDCl3) δ 139.2, 139.05, 139.03, 135.1, 128.92, 128.89, 128.8,
128.3, 128.2, 128.13, 128.09, 128.0, 117.8, 84.7, 79.5, 75.9, 75.7,
75.1, 74.0, 73.3, 69.2, 36.3; IR (thin film) 3030, 2860, 1496, 1454,
1362, 1129, 1093 cm-1; HRMS (EI/GCMS) m/z calcd for C29H32-
NaO4 (M + Na)+, 467.2198; found, 467.2191. Anal. Calcd for
C29H32O4: C, 78.35; H, 7.26. Found: C, 78.29; H, 7.05.
1-Allyl-2,3,4-tri-O-benzylarabinopyranose (31): Under stan-
dard allylation conditions using BF3‚OEt2 as a Lewis acid, acetate
30 (0.479 g, 1.04 mmol) afforded 31 (0.454 g, 99%) as a 68:32
1,4-trans/cis mixture of isomers. The isomers were resolved by
careful flash chromatography (hexanes to 1:9 Et2O/hexanes) to
allow for individual characterization.
1
1,4-trans Isomer (â Isomer): H NMR (500 MHz, CDCl3) δ
7.35-7.18 (m, 15H), 5.73-5.65 (m, 1H), 5.01 (m, 2H), 4.74 (m,
1H), 4.52 (m, 3H), 4.40 (m, 2H), 3.86 (m, 3H), 3.71 (m, 2H), 3.33
1
(m, 1H), 2.41-2.36 (m, 1H), 2.20-2.14 (m, 1H); H NMR (500
MHz, C6D6) δ 7.34-7.07 (m, 15H), 5.84 (m, 1H), 5.06 (m, 2H),
4.80 (d, J ) 12.1 Hz, 1H), 4.55 (d, J ) 12.1 Hz, 1H), 4.30-4.18
(m, 4H), 4.01-3.93 (m, 5H), 3.40-3.39 (dd, J ) 3.9, 1.6 Hz, 1H),
2.69-2.64 (m, 1H), 2.41-2.37 (m, 1H); 13C NMR (125 MHz,
CDCl3) δ 138.9, 138.7, 138.2, 135.2, 128.7, 128.6, 128.5, 128.2,
128.1, 128.0, 127.93, 127.90, 117.2, 76.5, 74.3, 73.3, 73.2, 73.0,
1-Allyl-2,3,4-tri-O-benzylribopyranose (23): Under standard
allylation conditions using BF3‚OEt2 as a Lewis acid, acetate 22
(0.371 g, 0.802 mmol) afforded 51 (0.237 g, 63%) as a 91:9 1,4-
cis/trans mixture of isomers. The oil was purified by flash
chromatography (hexanes to 1:9 Et2O/hexanes) to afford the 1,4-
72.7, 71.7, 64.8, 35.4; IR (thin film) 3030, 2868, 1454, 1096 cm-1
;
HRMS (EI/GCMS) m/z calcd for C29H32NaO4 (M + Na)+,
1
cis product: H NMR (500 MHz, CDCl3) δ 7.47-7.31 (m, 15H),
467.2198; found, 467.2213.
5.88-5.82 (m, 1H), 5.16-5.09 (m, 2H), 5.00 (d, J ) 11.8 Hz,
1H), 4.86 (d, J ) 12.5 Hz, 1H), 4.80-4.67 (m, 4H), 4.19-4.15
(dd, J ) 12.1, 4.5 Hz, 1H), 3.79-3.74 (m, 3H), 3.55 (m, 1H), 3.52-
3.49 (dd, J ) 12.1, 2.6 Hz, 1H), 2.85-2.79 (m, 1H), 2.51-2.45
(m, 1H); 1H NMR (500 MHz, C6D6) δ 7.40-7.08 (m, 15H), 6.00-
5.92 (m, 1H), 5.16-5.06 (m, 2H), 4.74 (m, 1H), 4.70 (d, J ) 12.1
Hz, 1H), 4.55 (d, J ) 12.2 Hz, 1H), 4.44-4.35 (m, 3H), 4.07-
4.03 (dd, J ) 11.6, 6.2 Hz, 1H), 3.60 (m, 2H), 3.43 (t, J ) 3.3 Hz,
1H), 3.34-3.32 (dt, J ) 6.1, 3.1 Hz, 1H), 3.30 (m, 1H), 3.00 (m,
1H), 2.61 (m, 1H); 13C NMR (125 MHz, CDCl3) δ 139.4, 139.2,
139.9, 136.0, 128.8, 128.7, 128.6, 128.5, 128.3, 127.92, 127.87,
127.81, 127.78, 117.3, 79.1, 78.6, 75.6, 73.6, 73.5, 72.2, 72.0, 34.9;
IR (thin film) 3029, 2866, 1453, 1358, 1108, 1066 cm-1; HRMS
(EI/GCMS) m/z calcd for C29H32NaO4 (M + Na)+, 467.2198; found,
467.2187.
1,4-cis Isomer (R Isomer): 1H NMR (500 MHz, CDCl3) δ 7.41-
7.18 (m, 15H), 5.94-5.89 (m, 1H), 5.09 (m, 2H), 4.89 (d, J )
10.8 Hz, 1H), 4.80 (d, J ) 12.7 Hz, 1H), 4.73-4.62 (m, 3H), 4.55
(d, J ) 12.0 Hz, 1H), 4.09 (dd, J ) 12.8, 2.1 Hz, 1H), 3.75 (m,
1H), 3.72 (t, J ) 9.2 Hz, 1H), 3.56-3.54 (dd, J ) 9.2, 3.2 Hz,
1
1H), 3.26-3.23 (m, 2H), 2.63 (m, 1H), 2.35 (m, 1H); H NMR
(500 MHz, C6D6) δ 7.37-7.07 (m, 15H), 6.15 (m, 1H), 5.14 (m,
2H), 5.02 (d, J ) 11.3 Hz, 1H), 4.55 (m, 2H), 4.40-4.20 (m, 3H),
3.90 (m, 2H), 3.34 (m, 2H), 3.27-3.23 (ddd, J ) 9.1, 7.8, 3.1 Hz,
1H), 2.83 (d, J ) 12.3 Hz, 1H), 2.71-2.69 (m, 1H), 2.47-2.44
(m, 1H); 13C NMR (125 MHz, CDCl3) δ 138.8, 138.6, 135.4,
128.63, 128.61, 128.6, 128.4, 128.2, 128.04, 127.92, 127.89, 127.86,
117.1, 83.2, 79.9, 78.6, 75.6, 72.7, 71.7, 71.3, 67.1, 36.5; 13C NMR
(125 MHz, C6D6) δ 139.3, 139.1, 138.7, 135.7, 128.5, 128.44,
128.39, 127.7, 127.62, 127.60, 127.5, 116.6, 77.6, 74.6, 74.2, 73.4,
73.3, 72.7, 71.3, 64.4, 35.6; IR (thin film) 2907, 2862, 1453, 1093
cm-1; HRMS (EI/GCMS) m/z calcd for C29H32O4 (M + Na)+,
467.2198; found, 467.2199.
1-Allyl-2,3,4-tri-O-benzylxylopyranose (27): Under standard
allylation conditions using BF3‚OEt2 as a Lewis acid, acetate 26
(0.158 g, 0.342 mmol) afforded 27 (0.100 g, 66%) as a 1:1 1,4-
trans/cis mixture of isomers.90 Careful flash chromatography
(hexanes to 1:9 Et2O/hexanes) provided a clean sample of the 1,4-
trans product: 1H NMR (500 MHz, CDCl3) δ 7.35-7.25 (m, 15H),
5.80 (m, 1H), 5.10 (m, 2H), 4.97 (d, J ) 11.0 Hz, 1H), 4.90 (d, J
) 10.8 Hz, 1H), 4.83 (d, J ) 11.0 Hz, 1H), 4.71 (d, J ) 11.6 Hz,
1H), 4.63-4.61 (d, J ) 11.7 Hz, 1H and d, J ) 10.8 Hz, 1H), 3.99
(dd, J ) 11.0, 5.0 Hz, 1H), 3.65-3.57 (m, 2H), 3.30-3.23 (m,
Acknowledgment. This research was supported by the
National Institutes of Health, National Institute of General
Medical Science (GM-61066). C.G.L. thanks the National
Institutes of Health for a predoctoral fellowship. K.A.W. thanks
Amgen, Johnson & Johnson, Eli Lilly and Company, and Merck
Research Laboratories for generous support for research. We
thank Professor A. R. Chamberlin (UCI) for helpful discussions,
Dr. John Greaves and Dr. John Mudd for mass spectrometric
data, and Dr. Phil Dennison for assistance with NMR studies.
1
2H), 3.16 (t, J ) 10.8 Hz, 1H), 2.61 (m, 1H), 2.20 (m, 1H); H
NMR (500 MHz, C6D6) δ 7.36-7.01 (m, 15H), 6.08-6.00 (m,
1H), 5.12 (m, 2H), 5.00 (d, J ) 11.4 Hz, 1H), 4.93 (d, J ) 11.3
Hz, 1H), 4.82 (d, J ) 11.3 Hz, 1H), 4.54 (d, J ) 11.4 Hz, 1H),
4.42 (d, J ) 11.9 Hz, 1H), 4.34 (d, J ) 11.9 Hz, 1H), 3.94-3.90
(dd, J ) 11.0, 5.0 Hz, 1H), 3.62-3.59 (t, J ) 9.0 Hz, 1H), 3.57-
3.51 (ddd, J ) 10.3, 9.1, 5.2 Hz, 1H), 3.25 (m, 2H), 3.08-3.03 (t,
J ) 11.0 Hz, 1H), 2.65-2.61 (m, 1H), 2.33-2.30 (m, 1H); 13C
NMR (125 MHz, CDCl3) δ 139.2, 138.73, 138.69, 135.1, 129.0,
128.93, 128.90, 128.40, 128.37, 128.32, 128.26, 128.1, 117.7, 86.9,
81.7, 79.7, 79.3, 76.0, 75.7, 73.7, 68.5, 36.7; IR (thin film) 3064,
3030, 2909, 2863, 1496, 1454, 1102 cm-1; HRMS (EI/GCMS) m/z
calcd for C29H32NaO4 (M + Na)+, 467.2198; found, 467.2186.
Supporting Information Available: Complete experimental
procedures, product characterization, stereochemical proofs, and GC
and spectral data for selected compounds. This material is available
JO0522963
J. Org. Chem, Vol. 71, No. 7, 2006 2647