LETTER
Site-Selective Oxidation and Metal-Induced 2-Propynylation of Pyranose Derivatives
2749
(CH), 130.1 (CH), 129.9 (CH), 128.8 (Ar), 128.73 (CH),
128.70 (Ar), 128.5 (CH), 128.2 (CH), 127.8 (CH), 126.9
the residue was redissolved in EtOH–H2O (95:5). NaIO4
(113 mg, 0.52 mmol) as an aq solution (1.1 mL) and NaBH4
(20 mg, 0.52 mmol) were added. After 4 h at r.t., the reaction
mixture was quenched by addition of dilute aq HCl and
extracted with Et2O. Chromatographic purification (EtOAc–
hexane 20:80) afforded 9 (267 mg, 72%). 1H NMR (250
MHz, CDCl3, TMS): d = 8.18–8.14 (m, 2 H, ArH), 7.87–
7.83 (m, 2 H, ArH), 7.60–7.05 (m, 21 H, ArH), 5.65 (t,
J = 9.7 Hz, 1 H, CH), 5.42–5.41 (m, 1 H, CH), 5.10 (s, 1 H,
CH), 4.34 (dd, J = 9.4 Hz, J = 3.4 Hz, 1 H, CH), 4.17–4.09
(m, 1 H, CH), 3.97–3.79 (m, 4 H, 2 × CH2), 3.31–3.29 (m, 2
H, CH2), 0.62 [s, 9 H, SiC(CH3)3], 0.04 (s, 3 H, SiCH3),
–0.16 (s, 3 H, SiCH3). 13C NMR and DEPT (63 MHz): d =
166.1 (CO), 164.9 (CO), 143.6 (Ar), 133.2 (ArH), 132.8
(ArH), 129.9 (ArH), 129.71 (Ar), 129.69 (Ar), 129.6 (ArH),
128.5 (ArH), 128.4 (ArH), 128.1 (ArH), 127.6 (ArH), 126.7
(ArH), 98.3 (CH), 86.7 (C), 72.7 (CH), 70.8 (CH), 70.6
(CH2), 69.7 (CH), 68.9 (CH), 62.6 (CH2), 61.9 (CH2), 25.2
[SiC(CH3)3], 17.5 [SiC(CH3)3], –4.8 (SiCH3), –5.2 (SiCH3).
MS: m/z (%) = 485 (81) [M+ – CH2CH2OH – OCPh3], 243
(CH), 118.5 (OCH2CHCH2), 98.4 (CH), 86.6 (C), 76.6 (CH),
25
72.53 (CH), 72.47 (CH), 68.5 (CH2), 61.8 (CH2). [a]D
+12.0 (c 1.2, CHCl3).
Allyl 2,4-Bis-O-Benzoyl-3-benzyloximino-6-O-trytil-b-D-
mannopyranoside: 1H NMR (250 MHz, CDCl3, TMS): d =
8.16–8.12 (m, 2 H, ArH), 7.86–7.83 (m, 2 H, ArH), 7.64–
7.07 (m, 26 H, ArH), 6.49 (d, J = 1.4 Hz, 1 H, CH), 6.12 (d,
J = 10.2 Hz, 1 H, CH), 6.00–5.87 (m, 1 H, OCH2CHCH2),
5.36–5.21 (m, 3 H, OCH2CHCH2 + CH), 5.03 (s, 2 H,
NOCH2Ar), 4.32–4.25 (m, 2 H, OCH2CHCH2), 4.16–4.08
(m, 1 H, CH), 3.46 (dd, J = 10.3 Hz, J = 1.9 Hz, 1 H, CH2),
3.30 (dd, J = 10.3 Hz, J = 4.2 Hz, 1 H, CH2). 13C NMR and
DEPT (63 MHz): d = 165.1 (CO), 164.7 (CO), 146.9
(CNOBn), 143.6 (Ar), 137.3 (Ar), 133.4 (CH), 133.2 (CH),
132.9 (CH), 130.0 (CH), 129.8 (CH), 129.5 (Ar), 129.2 (Ar),
128.5 (CH), 128.1 (CH), 128.0 (CH), 127.7 (CH), 127.5
(CH), 126.8 (CH), 117.8 (OCH2CHCH2), 96.7 (CH), 86.4
(C), 76.5 (NOCH2Ar), 71.5 (CH), 68.1 (CH2), 66.1 (CH),
64.7 (CH), 62.0 (CH2). [a]D25 –11.2 (c 1.2, CHCl3).
Allyl 2,4-Bis-O-Benzoyl-3-benzyloximino-b-D-
(51) [CPh3 ], 105 (100) [Bz+]. [a]D25 –6.9 (c 1.2, CHCl3).
+
Spiroorthoester 10: (Diacetoxy)iodobenzene (146 mg, 0.43
mmol) and I2 (99 mg, 0.39 mmol) were added to a solution
of the 2-hydroxyethyl mannopyranoside 9 (309 mg, 0.39
mmol) in cyclohexane (30 mL, 0.01 M) under argon. After
irradiating with a 100 W sunlamp for 7 h, the reaction
mixture was washed with a sat. aq solution of Na2S2O3 and
extracted with Et2O. Column chromatography (EtOAc–
hexane 10:90) afforded 10 (145 mg, 47%). 1H NMR (250
MHz, CDCl3, TMS): d = 8.20–8.17 (m, 2 H, ArH), 7.87–
7.84 (m, 2 H, ArH), 7.60–7.06 (m, 21 H, ArH), 5.74 (t,
J = 10.0 Hz, 1 H, CH), 5.57 (d, J = 3.1 Hz, 1 H, CH), 4.35
(dd, J = 9.4 Hz, J = 3.1 Hz, 1 H, CH), 4.29–3.98 (m, 5 H,
2 × CH2 + CH), 3.33–3.30 (m, 2 H, CH2), 0.64 [s, 9 H,
SiC(CH3)3], 0.09 (s, 3 H, SiCH3), –0.14 (s, 3 H, SiCH3).
13C NMR and DEPT (63 MHz): d = 165.8 (CO), 164.8 (CO),
143.8 (Ar), 133.0 (ArH), 132.8 (ArH), 130.0 (ArH), 129.9
(Ar), 129.8 (Ar), 129.6 (ArH), 128.6 (ArH), 128.4 (ArH),
128.1 (ArH), 127.6 (ArH), 126.7 (ArH), 117.4 (OCO), 86.5
(C), 72.7 (CH), 72.5 (CH), 70.9 (CH), 69.5 (CH), 65.2
(CH2), 64.7 (CH2), 62.7 (CH2), 25.2 [SiC(CH3)3], 17.5
[SiC(CH3)3], –4.8 (SiCH3), –5.2 (SiCH3). MS (electron
impact): m/z (%) = 730 (0.1) [M+ – C(CH3)3], 243 (100)
mannopyranoside: 1H NMR (250 MHz, CDCl3, TMS): d =
8.10–8.07 (m, 4 H, ArH), 7.66–7.26 (m, 11 H, ArH), 6.50 (d,
J = 1.6 Hz, 1 H, CH), 6.05 (d, J = 10.0 Hz, 1 H, CH), 6.01–
5.87 (m, 1 H, OCH2CHCH2), 5.38–5.24 (m, 2 H,
OCH2CHCH2), 5.19 (d, J = 1.3 Hz, 1 H, CH), 5.11 (s, 2 H,
NOCH2Ar), 4.36–4.07 (m, 3 H, OCH2CHCH2 + CH), 3.93–
3.80 (m, 2 H, CH2). 13C NMR and DEPT (63 MHz): d =
165.4 (CO), 165.0 (CO), 146.6 (CNOBn), 137.2 (Ar), 133.5
(CH), 133.4 (CH), 133.0 (CH), 129.9 (CH), 129.3 (Ar),
129.0 (Ar), 128.5 (CH), 128.4 (CH), 128.2 (CH), 128.1
(CH), 127.6 (CH), 118.0 (OCH2CHCH2), 96.9 (CH), 76.6
(NOCH2Ar), 72.1 (CH), 68.3 (CH2), 65.6 (CH), 64.6 (CH),
61.6 (CH2). MS (IQ+ low resolution): m/z (%) = 532 (94) [M+
+ 1], 474 (100) [M+ – OAllyl], 410 (71) [M+ – Obz]. [a]D
–25.1 (c 1.2, CHCl3).
25
1-O-Allyl-2,4-Bis-O-Benzoyl-3-deoxy-3-benzyloxyimino-
6-aldehydo-b-D-arabino-hexopyranose (IIIc): 1H NMR
(250 MHz, CDCl3, TMS): d = 9.76 (d, J = 1.2 Hz, 1 H,
CHO), 8.08–8.05 (m, 4 H, ArH), 7.64–7.44 (m, 6 H, ArH),
7.26–7.21 (m, 5 H, ArH), 6.46 (d, J = 1.4 Hz, 1 H, CH), 6.10
(d, J = 10.2 Hz, 1 H, CH), 5.88–6.04 (m, 1 H,
OCH2CHCH2), 5.37–5.24 (m, 2 H, OCH2CHCH2), 5.09 (s, 2
H, NOCH2Ar), 5.06–5.02 (m, 1 H, CH), 4.55 (d, J = 11.0 Hz,
1 H, CH), 4.33–4.15 (m, 2 H, OCH2CHCH2). 13C NMR and
DEPT (63 MHz): d = 195.7 (CHO), 170.5 (CO), 164.9 (CO),
145.2 (CNOBn), 141.8 (CH), 136.9 (Ar), 133.3 (CH), 132.6
(CH), 131.8 (CH), 129.97 (Ar), 129.95 (CH), 129.91 (Ar),
128.5 (CH), 128.4 (CH), 128.2 (CH), 128.1 (CH), 127.9
(CH), 127.7 (CH), 118.4 (OCH2CHCH2), 97.0 (CH), 76.8
(NOCH2Ar), 74.5 (CH), 68.8 (CH2), 64.9 (CH), 64.2 (CH).
[a]D25 –17.5 (c 1.2, CHCl3).
+
[C(Ph)3 ], 165 (24), 105 (100) [Bz+]. MS (chemical
ionization, CH4): m/z (%) = 545 (11) [M+ – C(Ph)3], 243
+
(100) [C(Ph)3 ]. [a]D25 –19.3 (c 1.1, CHCl3).
(12) Alcaide, B.; Almendros, P.; Aragoncillo, C. Org. Lett. 2000,
2, 1411.
(13) (a) Anies, C.; Lallemamd, J.-Y.; Pancrazi, A. Tetrahedron
Lett. 1996, 37, 5519. (b) Hiraoka, H.; Furuta, K.; Ikeda, N.;
Yamamoto, H. Bull. Chem. Soc. Jpn. 1984, 57, 2768.
(14) Harada, N.; Saito, A.; Ono, H.; Murai, S.; Li, H.-Y.;
Gawronski, J.; Gawronska, K.; Sugioka, T.; Uda, H.
Enantiomer 1996, 1, 119.
(15) CCDC 244334 contains the supplementary crystallographic
data for 16a. These data can be obtained free of charge via
data_request@ccdc.cam.ac.uk, or by contacting The
Cambridge Crystallographic Data Centre, 12, Union Road,
Cambridge CB2 1EZ, UK; fax: +44 (1223)336033.
(16) Zn-Promoted 2-Propynylation of C6-Sugar Aldehydes:
IIIc → 11:
(10) (a) Suárez and co-workers recently reported on the synthesis
of chiral spiroacetals from carbohydrates under similar
conditions: Martín, A.; Salazar, J. A.; Suárez, E. J. Org.
Chem. 1996, 61, 3999. (b) For the transformation of fully
acetate-protected D-glucosyl halides into spiroorthoesters,
see: Praly, J. P.; Descotes, G. Tetrahedron Lett. 1982, 23,
849.
(11) Radical-Based Site-Selective Oxidation of Allyl
Glycoside Derivatives into Anomeric Spiroorthoesters:
2-Hydroxyethyl 2,4-Bis-O-Benzoyl-3-O-(tert-
Zn dust (80 mg, 1.21 mmol) and propargylic bromide (68
mL, 0.60 mmol) were added in two portions to aldehyde IIIc
(54 mg, 0.10 mmol) in a mixture of THF and aq sat. NH4Cl
(1:5, 5 mL) at r.t. After 6 h at r.t. and 2 h at 70 °C, the
reaction mixture was diluted with brine and extracted with
butyldimethylsilyl)-6-O-trytil-b-D-mannopyranoside (9):
To a solution of the allyl mannopyranoside 78 (369 mg, 0.47
mmol) in acetone–H2O (8:2), N-methyl morpholine oxide
(54 mg, 0.52 mmol) and OsO4 (cat.), were added. After one
day at r.t., the solvent was removed under reduced pressure,
Synlett 2004, No. 15, 2746–2750 © Thieme Stuttgart · New York