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Green Chemistry
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Journal Name
ARTICLE
CH,CH2); 3.45-3.49, 3.62-3.66(m, 4H, CH2O); 4.28-4.30(d, 1H, 15.02(Me); 61.22(CH2); 100.06(CH); 123.27, 127.62(CH-Ph);
13C NMR (100.61 MHZ) (CDCl3):
15.29(Me-(CH2O)); 20.77(CH2-CH);
146.08(C-CHO); 147.80(C-NO2).
DOI: 10.1039/C6GC03629E
CHO, J = 6.0 MHZ).
11.00(Me-(CH2CH));
4-methoxybenzaldehydediethylacetal (A16): 1H NMR (400
43.56(CH-CH2); 61.98(CH2-O); 105.26(CH-O).
2,2-dipheylacetaldehyde diethylacetal (A7): 1H NMR (400 3.53;3.58-3.62(m, 4H, H2); 3.78(s, 3H, H8); 5.45(s, 1H, H3);
MHz) (CDCl3): .1.13-1.16(t, 6H, Me, J = 7.2 MHZ); 3.50-3.54, 6.86-6.88(d, 2H, H5, J = 8.8MHZ); 7.37-7.40(d, 2H, H6, J = 8.4
3.70-3.74(m, 4H, CH2); 4.32-4.34(d, 1H, CH-Ph, J = 7.6 MHZ); MHZ). 15.07(Me);
13C NMR (100.61 MHZ) (CDCl3):
5.15-5.17(d, 1H, CH-O, J = 7.6 MHZ); 7.23-7.44(m, 10H, CH-Ph). 55.07(MeO); 60.73(CH2O); 101.29(CH); 113.36, 127.72(CH-Ph);
13C NMR (100.61 MHZ) (CDCl3):
. 14.97(Me-CH2O); 55.29(CH- 131.35(C-CH); 159.45(C-OMe).
MHz) (CDCl3): 1.20-1.24(t, 6H, H1, J = 7.2 MHZ); 3.49-
Ph); 62.33(CH2); 104.72(CH-O); 126.13, 128.03, 128.83,
129.03(CH-Ph); 141.29(C-Ph).
4-methylbenzaldehyde diethylacetal (A17): 1H NMR (400
MHz) (CDCl3): .1.25-1.29(t, 6H, Me-(CH2O), J = 7.2 MHZ);
Cyclohexanecarboxaldehyde diethylacetal (A8): 1H NMR 2.38(s, 3H, Me); 3.54-3.67(m, 4H, CH2); 5.52(s, 1H, CH-O);
(400 MHz) (CDCl3):
1.17-1.20(t, 6H, Me, J = 7.2 MHZ); 3.43-3.50, 3.59-3.67(m, 4H, = 7.6 MHZ).
CH2-O); 4.09-4.11(d, 1H, CH-O, J = 7.2 MHZ). 13C NMR (100.61 CH2O); 21.09(Me-Ph); 60.84(CH2); 101.52(CH-O); 126.49,
MHZ) (CDCl3): 15.28(Me); 25.80, 26.43, 28.19(CH2); 128.75(CH-Ph); 136.15(C-CHO); 137.85(C-Me).
.0.91-1.5, 1.51-1.80(m, 11H, CH2 and CH); 7.19-7.21(d, 2H, CH-Ph, J = 7.6 MHZ); 7.39-7.41(d, 2H, CH-Ph, J
13C NMR (100.61 MHZ) (CDCl3):
. 15.13(Me-
.
40.79(CH-Cyclohex); 61.59(CH2-O); 106.77(CH-O).
Benzaldehyde diethylacetal (A9): 1H NMR (400 MHz)
Conclusions
(CDCl3):
CH2O); 5.52(s, 1H, CHO); 7.31-7.38, 7.48-7.50(m, 5H, Ph). 13C
NMR (100.61 MHZ) (CDCl3): 15.12(Me); 60.91(CH2);
1.23-1.27(t, 6H, Me, J = 7.2MHZ); 3.53-3.65(m, 4H,
We have developed a new, efficient and environmentally-
benign process for the acetalisation of a variety of aldehydes
that is catalysed by the potent Lewis acidic stibonium cation
101.48(CHO); 126.57, 128.07, 128.18(CH-Ph); 139.05(C-Ph).
2,3,4,5,6-pentafluorobenzaldehyde diethylacetal (A10): 1H
[1][OTf]. The speed of the reactions were found to increase
NMR (400 MHz) (CDCl3):
3.55-3.59, 3.74-3.78(m, 4H, CH2); 5.70(s, 1H, CH). 13C NMR
(100.61 MHZ) (CDCl3): 14.90(Me); 63.70(CH2); 96.52(CH);
113.22, 136.26, 138.77, 143.53, 146.06(C-F).
19F
NMR(376.4983 MHz) : . -162.09, -154.28, -142.62. Elemental
.1.22-1.26(t, 6H, Me, J = 7.2 MHZ);
from aromatic to aliphatic derivatives, and longer reaction
times were observed when for electron-withdrawing groups
were incorporated into the aldehyde. The use of
triethoxysilane as an ethoxide source resulted in rapid reaction
times when compared to triethoxymethane. The easy to
handle nature, stability, and lower loading (0.1mol %) of
analysis calculated (%) for C11H11F5O2: C. 48.90, H 4.10. Found:
C. 48.66, H. 4.09.
[1][OTf] provides an elegant, rapid, and green method for
2-bromobenzaldehydediethylacetal (A11): 1H NMR (400
protecting aldehydes. Additionally, the requirement of only a
stoichiometric quantity of alkoxide source (i.e.: 1:1 ratio
aldehyde triethoxy derivative) as opposed to excess alcohol,
acid, or other alkoxide source offers synthetic chemists with a
superior method for protecting aldehydes. Further studies and
calculations are underway in an effort to fully elucidate the
mechanism involved in these transformations, however our
previous studies suggest the key success of these reactions is
rooted in the potent Lewis acidity of the stibonium centre.35
MHz) (CDCl3):
4H, CH2); 5.27(s, 1H, CHO); 7.14-7.16, 7.30-7.34, 7.52(m, 4H,).
13C NMR (100.61 MHZ) (CDCl3):
3-bromobenzaldehyde diethylacetal (A12): 1H NMR (400
MHz) (CDCl3): .1.24-1.27(t, 6H, Me, J = 6.8 MHZ); 3.55-3.67(m,
4H, CH2); 5.48(s, 1H, CH); 7.22-7.26, 7.40-7.45, 7.65-7.66(m,
4H, CH-Ph). 13C NMR (100.61 MHZ) (CDCl3):
. 15.09(Me);
1.23-1.27(t, 6H, Me, J = 7.2 MHZ); 3.54-3.71(m,
61.03(CH2); 100.47(CH); 122.35(C-Br); 125.28, 129.72, 129.79,
131.28(CH-Ph); 141.42(C-CHO).
3-fluorobenzaldehyde diethylacetal (A13): 1H NMR (400
MHz) (CDCl3):
3.64(m, 4H, CH2); 5.50(s, 1H, CH); 6.97-7.02, 7.19-7.35(m, 4H,
CHPh). 13C NMR (100.61 MHZ) (CDCl3):
. 15.09(Me);
61.01(CH2); 100.58(CH); 113.57-113.79, 114.95-115.16,
122.27, 129.67(CH-Ph); 141.82(C-CHO); 164.04(C-F). 19F
. 1.22-1.26(t, 6H, Me, J = 7.2 MHZ); 3.52-
Acknowledgements
The authors would like to acknowledge the Donors of the
American Chemical Society – Petroleum Research Fund for
grant 54584-UR3 (TWH), The National Science Foundation for
grants CHE-0821254 and CHE-0946998 (MRI), and the Welch
Foundation for a Department Research Grant (AI-0045).
NMR(376.4983 MHz) :
4-trifluorobenzaldehyde diethylacetal (A14): 1H NMR (400
MHz) (CDCl3): .1.22-1.26(t, 6H, Me, J = 7.2 MHZ); 3.52-3.63(m,
4H, CH2); 5.54(s, 1H, CH-O); 7.60-7.62(m, 4H, CH-Ph). 13C NMR
(100.61 MHZ) (CDCl3): .15.11(Me); 61.15(CH2); 100.65(CH-O);
125.09(C-F); 125.14, 127.08(CH-Ph); 129.50(C-CF3), 143.13(C-
CHO). 19F NMR(376.4983 MHz) :
. -62.58
4-nitrobenzaldehyde diethylacetal (A15): 1H NMR (400
MHz) (CDCl3): .1.22-1.26(t, 6H, Me, J = 7.2 MHZ); 3.54-3.61(m,
. -113.36
Notes and references
‡ Footnotes relating to the main text should appear here. These
might include comments relevant to but not central to the
matter under discussion, limited experimental and spectral data,
and crystallographic data.
1. a) J. R. Hanson, Black-Well Science, Inc, Malden, MA, 1st edn.,
1999; b) T. W. Greene and P. G. M. Wuts, John Willey and Sons,
4H, CH2); 5.57(s, 1H, CH); 7.65-7.67(d, 2H, CH-Ph, J = 8.8 MHZ);
8.19-8.21(d, 2H, CH-Ph, 8.8). 13C NMR (100.61 MHZ) (CDCl3):
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