Communication
using a very common reagent as the catalyst was presented. In Acknowledgments
addition, it was demonstrated in this paper that a reaction mix-
H. W. R. thanks the Deutsche Forschungsgemeinschaft for finan-
cial support (RO 224/68-1). P. P. and S. D. thank the Department
of Science and Technology (DST), India for funding.
ture containing the gem-diazide could be directly used for the
clean synthesis of a stable gem-bis(triaza-1,3-butadiene) com-
pound. In addition, gem-diazides were shown to undergo the
Staudinger reaction with triphenylphosphane, which further re-
sulted in the elimination of a hydride ion from the central car-
bon atom in the presence of triflic acid. The applications of the
products reported herein are under investigation in our labora-
tory.
Keywords: Aldehydes · Azides · Carbenes · Phosphanes ·
Silyl cyanation
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Synthesis of B: Benzaldehyde (0.106 g, 1 mmol) was treated with
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1
purification could be done by washing with n-hexane (10 mL). Yield:
1
0
.922 g (97 %). M.p. 179 °C (decomp.). H NMR (400 MHz, C D ): δ =
6
6
2
0
.94 [d, 12 H, CH(CH ) ], 1.11 [d, 12 H, CH(CH ) ], 1.20 [d, 12 H,
3
2
3 2
[
CH(CH ) ], 1.23 [d, 12 H, CH(CH ) ], 2.85 [sept, 4 H, CH(CH ) ], 3.02
3
2
3 2
3 2
2
[
sept, 4 H, CH(CH ) ], 4.57 [s, 1 H, CH(N) ], 5.82 [s, 4 H, CH(N)], 6.73–
3 2 2
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6
.77 (m, 2 H, ArH), 6.93–7.14 (m, 11 H, ArH), 7.25–7.28 (m, 4 H,
13
ArH) ppm. C NMR (100 MHz, C D ): δ = 23.02, 23.80, 23.98, 24.04
6
6
[
CH(CH ) ], 29.11, 29.32 [CH(CH ) ], 96.93 [CH(N) ], 116.59 [CH(N)],
3 2 3 2 2
1
23.96, 124.25 (m-C, Dipp), 125.70 (p-C, Ph), 126.14 (o-C, Ph), 127.54
[
(
m-C, Ph), 129.37, 129.56 (p-C, Dipp), 142.71 [C-CH(CH ) ], 145.93 (i-
3 2
C, Ph), 146.36 (N-C, Dipp), 153.78 (C=N, NHC) ppm. MS (ESI): m/z =
[
+
9
51.6 [M + H] . C H N (951.34): calcd. C 77.01, H 8.26, N 14.72;
61 78 10
found C 77.03, H 8.22, N 13.99.
[
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Synthesis of C: Benzaldehyde (0.106 g, 1 mmol) was treated with
trimethylsilyl azide (0.230 g, 2 mmol) in the presence of triflic acid
1
2469.
(
0.1 mol-%) in benzene (4 mL) at room temperature for 6 h. Triphen-
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ylphosphane (0.525 g, 2 mmol) was added, and the mixture was
stirred for 2 d. Benzene was removed in vacuo, and the flask was
recharged with toluene (10 mL). After cooling to –78 °C, a solution
of triflic acid (150 mg, 2 mmol) in toluene (10 mL) was added whilst
stirring, and the temperature was slowly allowed to reach room
temperature. A white precipitate started to deposit on the surface
of the flask; it was collected after decanting the supernatant solu-
tion. The precipitate was washed repeatedly with hexane to afford
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725–1726.
a fine powder, which was then crystallized from hot toluene. Yield:
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1
2
20 mg (28 %). H NMR (500 MHz, CDCl ): δ = 6.89–6.92 (m, 2 H,
3
m-H, Ph-C), 7.02–7.03 (m, 2 H, o-H, Ph-C), 7.08–7.11 (m, 1 H, p-H,
Ph-C), 7.35–7.39 (o,m-H, 24 H, Ph-P), 7.58–7.61 (6 H, p-H, Ph-P) ppm.
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13
C NMR (125 MHz, C D ): δ = 125.01 (d, J = 101.52 Hz, i-C, Ph-
6
6
P, C
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P), 126.46 (s, o-C, Ph-C), 127.88 (s, m-C, Ph-C), 129.28 (d, JP, C
=
1
2.96 Hz, m-C, Ph-P), 129.61 (s, p-C, Ph-C), 132.50 (d, JP, C = 10.32 Hz,
o-C, Ph-P), 133.50 (d, JP, C = 2.64 Hz, p-C, Ph-P), 139.202 (t, J
=
P, C
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2160.
19
1
2.07 Hz, i-C, Ph-C), 178.42 (t, JP, C = 6.29 Hz, NCN) ppm. F NMR
3
1
(282 MHz, CDCl ): δ = –77.99 (s, CF ) ppm. P NMR (121 MHz,
3
3
+
CDCl ): δ = 16.71 (PPh ) ppm. MS (LIFDI): m/z = 641 [M – OTf] .
3
3
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4
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