Abstracts
Sc(OTf)3 was found to be an efficient catalyst for the C-glycosylation of phenols. Reactions of various functionalized phenols and glycosyl acetates, including an azido-bearing one, are achieved by using a catalytic amount of Sc(OTf)3 (10 mol% for neutral sugars or 50 mol% for an azido sugar) under mild conditions.
Key words
aryl C -glycosides -
O →C -glycoside rearrangement - scandium triflate - catalysis - ravidomycin
References
1a Hacksell U.
Daves GD.
Prog. Med. Chem.
1985,
22:
1
1b Suzuki K.
Matsumoto T. In
Recent Progress in the Chemical Synthesis of Antibiotics and Related Microbial Products
Vol. 2:
Lukacs G.
Springer;
Berlin:
1993.
p.353
1c Levy DE.
Tang C.
The Chemistry of C-Glycosides
Pergamon;
Oxford:
1995.
1d Postema MHD.
C-Glycoside Synthesis
CRC;
Florida:
1995.
2a Matsumoto T.
Katsuki M.
Suzuki K.
Tetrahedron Lett.
1988,
29:
6935
2b Kometani T.
Kondo H.
Fujimori Y.
Synthesis
1988,
1005
3a O →C -glycoside rearrangement, see: Vineomycinone B2 methyl ester: Matsumoto T.
Katsuki M.
Jona H.
Suzuki K.
J. Am. Chem. Soc.
1991,
113:
6892
3b Matsumoto T.
Hosoya T.
Suzuki K.
J. Am. Chem. Soc.
1992,
114:
3568
3c Hosoya T.
Takashiro E.
Matsumoto T.
Suzuki K.
J. Am. Chem. Soc.
1994,
116:
1004
3d Matsumoto T.
Sohma T.
Yamaguchi H.
Kurata S.
Suzuki K.
Synlett
1995,
263
3e Matsumoto T.
Sohma T.
Yamaguchi H.
Kurata S.
Suzuki K.
Tetrahedron
1995,
51:
7347
3f Matsumoto T.
Yamaguchi H.
Suzuki K.
Synlett
1996,
433
3g Matsumoto T.
Yamaguchi H.
Suzuki K.
Tetrahedron
1997,
53:
16533
3h Futagami S.
Ohashi Y.
Imura K.
Hosoya T.
Ohmori K.
Matsumoto T.
Suzuki K.
Tetrahedron Lett.
2000,
41:
1063
3i Matsumoto T.
Yamaguchi H.
Tanabe M.
Kuriyama Y.
Yasui Y.
Suzuki K.
Tetrahedron Lett.
2000,
41:
8393
3 ·OEt2 in O →C -glycoside rearrangement, see ref. 2a,b. See also:
4a Brimble MA.
Davey RM.
McLeod MD.
Murphy M.
Aust. J. Chem.
2003,
56:
787
4b Kumazawa T.
Onda K.
Okuyama H.
Matsuba S.
Sato S.
Onodera J.
Carbohydr. Res.
2002,
337:
1007
4c Andrews FL.
Larsen DS.
Larsen L.
Aust. J. Chem.
2000,
53:
15
4d 4 , see: Matsumoto T.
Hosoya T.
Suzuki K.
Tetrahedron Lett.
1990,
31:
4629
4e Mahling J.-A.
Schmidt RR.
Synthesis
1993,
325
4f Toshima K.
Matsuo G.
Ishizuka T.
Ushiki Y.
Nakata M.
Matsumura S.
J. Org. Chem.
1998,
63:
2307
2 MCl2 -AgX (M = Zr, Hf), see:
5a Matsumoto T.
Maeta H.
Suzuki K.
Tsuchihashi G.
Tetrahedron Lett.
1988,
29:
3567
5b Suzuki K.
Pure Appl. Chem.
1994,
66:
2175
6a Matsumoto T.
Katsuki M.
Jona H.
Suzuki K.
Tetrahedron Lett.
1989,
30:
6185
6b Hosoya T.
Ohashi Y.
Matsumoto T.
Suzuki K.
Tetrahedron Lett.
1996,
37:
663
7a Findlay JA.
Liu J.-S.
Radics L.
Rakhit S.
Can. J. Chem.
1981,
59:
3018
7b Findlay JA.
Liu J.-S.
Radics L.
Can. J. Chem.
1983,
61:
323
7c Sehgal SN.
Czerkawski H.
Kudelski A.
Pandev K.
Saucier R.
Vezina C.
J. Antibiot.
1983,
36:
355
7d Narita T.
Matsumoto M.
Mogi K.
Kukita K.
Kawahara R.
Nakashima T.
J. Antibiot.
1989,
42:
347
8a 3 in organic synthesis: Kobayashi S.
Eur. J. Org. Chem.
1999,
15
8b Kobayashi S. In Lewis Acids in Organic Synthesis
Vol. 2:
Yamamoto H.
Wiley-VCH;
Weinheim:
2000.
p.883
8c Kobayashi S.
Hachiya I.
Araki M.
Ishitani H.
Tetrahedron Lett.
1993,
34:
3755
3 in O-glycosidation, see:
9a Hashizume N.
Kobayashi S.
Carbohydr. Lett.
1996,
2:
157
9b Fukase K.
Kinoshita I.
Kanoh T.
Nakai Y.
Hasuoka A.
Kusumoto S.
Tetrahedron
1996,
52:
3897
9c Yamanoi T.
Yamazaki I.
Tetrahedron Lett.
2001,
42:
4009
10 This work was presented at the 83rd Annual Meeting of the Chemical Society of Japan, March 2003, Tokyo, Abstract 2D-1-38.
11 The α-isomer was used for this study. Synthesis of 2 will be reported elsewhere.
12 Hamura T.
Hosoya T.
Yamaguchi H.
Kuriyama Y.
Tanabe M.
Miyamoto M.
Yasui Y.
Matsumoto T.
Suzuki K.
Helv. Chim. Acta
2002,
85:
3589
13 Selected data of 1 H NMR, 13 C NMR, NOE and HMBC are shown below (Figure
[2
14 Experimantal procedure as follows: To a stirred mixture of Sc(OTf)3 (210 mg, 0.427 mmol; Aldrich, 99.995%), phenol 3 (417 mg, 1.28 mmol), powdered Drierite® (2.6 g) in 1,2-dichloroethane (15 mL), was added acetate 2 (361 mg, 0.878 mmol) in 1,2-dichloroethane (8 mL) at -30 °C. After the temperature was gradually raised to 12 °C during 0.5 h, the mixture was poured into sat. aq NaHCO3 solution. After filtration through a Celite pad, the products were extracted with EtOAc (3×), and the combined organic extracts were washed with brine, and dried over Na2 SO4 . Removal of the solvents in vacuo and purification by silica-gel column chromatography (hexane/EtOAc = 5:1) afforded C -glycoside β-4 as white powder (462 mg, 78%).
15 Typical experimental procedure for the aryl C-glycosylation of neutral sugars is described for the reaction of phenol 3 and glycosyl acetate 5a : To a stirred mixture of Sc(OTf)3 (6.7 mg, 14 µmol), phenol 3 (87.7 mg, 0.269 mmol), powdered Drierite® (403 mg) in 1,2-dichloroethane (1.5 mL), was added acetate 5a (49.8 mg, 0.134 mmol) in 1,2-dichloroethane (1.0 mL) at -30 °C. After the temperature was gradually raised to -10 °C during 1.0 h, the reaction was quenched with sat. aq NaHCO3 solution. After filtration through a Celite pad, the products were extracted with EtOAc (3×), and the combined organic extracts were washed with brine, and dried over Na2 SO4 . Removal of the solvents in vacuo and purification on silica-gel preparative TLC (hexane/acetone = 2:1) afforded C -glycoside 6a as white powder (75.9 mg, 89%).
