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Et2O (25 mL), the mixture was stirred overnight at room tempera-
ture. Water (200 mL, distilled) was then added, and the phases
were separated. The aqueous phase was extracted with Et2O (3
100 mL), and the combined organic phases were dried (MgSO4).
After removal of the solvent at reduced pressure, a crude residue
(550 mg) was obtained as a viscous yellow liquid, which was puri-
fied by flash chromatography (silica gel, Et2O/hexane 1:6). The first
fractions included 15c (105 mg) and trisyl azide (4 mg), whereas
the last fraction consisted of 17[20] (10 mg, 0.037 mmol, 2%). The
medium fraction (161.5 mg) consisted of 14c (0.41 mmol, 20%)
and 16c (0.004 mmol, 0.2%), which could be separated by re-
newed flash chromatography (silica gel, Et2O/hexane 1:10).
azide, as described for the reaction of 15c. After addition of the
azide, the mixture was stirred for 90 min at À458C before it was
slowly warmed up to room temperature. After treatment with
Na4P2O7·10H2O and the usual workup, a crude orange-brown oil
(371 mg) was obtained. Purification by flash chromatography (silica
gel, Et2O/hexane 1:6) led to the first fraction, including a mixture of
unreacted 15d and trisyl azide (182 mg), followed by a fraction
with 3d[22] (64 mg, 0.23 mmol, 15%) and finally a fraction with 5d
(16 mg, 0.060 mmol, 4%).
2,3,3-Triphenylacrylonitrile (3d): Light-yellow solid; m.p. 1668C
(CHCl3; ref. [22]: 166–1678C); 1H NMR (CDCI3): d=7.00–7.02 (m,
2H), 7.17–7.28 (m, 9H), 7.42–7.48 ppm (m, 4H); 13C NMR (CDCI3):
d=111.53 (s, CN), 120.10 (s, PhCCN), 128.18 (d), 128.30 (d), 128.40
(d), 128.43 (d), 128.94 (d), 129.65 (d), 129.83 (d), 129.87 (d), 130.73
(d), 134.75 (s), 138.99 (s), 140.34 (s), 157.72 ppm (s, Ph2CCCN); IR
(CDCI3): n˜ =3062, 3028 (s, CH), 2210 (CꢁN), 1598 cmÀ1 (m, C=C).
5-tert-Butyl-1-(2,4,6-triisopropylphenylsulfonyl)-1H-1,2,3-triazole
(14c): White solid; m.p. 114–1178C (CHCl3); 1H NMR (CDCI3): d=
1.18 (d, 3J=6.8 Hz, 12H, ortho-CH(CH3)2), 1.28 (d, 3J=6.8 Hz, 6H,
para-CH(CH3)2), 1.58 (s, 9H, C(CH3)3), 2.94 (sept, 3J=6.8 Hz, 1H,
3
para-CH(CH3)2), 3.82 (sept, J=6.8 Hz, 2H, ortho-CH(CH3)2), 7.23 (s,
2H, CCHC), 7.45 ppm (s, 1H, CCHN); in homonuclear NOE experi-
ments, irradiation at the frequency of the H4 atom indicated an
effect at the signal of the tert-butyl group exclusively (see
Scheme 3); 13C NMR (CDCI3): d=23.45 (q), 24.14 (d), 29.78 (q), 29.98
(d), 31.75 (s, C(CH3)3), 34.37 (q), 124.20 (d), 130.86 (s), 131.79 (d),
148.19 (s), 152.59 (s), 155.62 ppm (s); IR (CDCI3): n˜ =2966, 2934,
2872 (s, CH), 1186 cmÀ1 (s, SO2ÀN); MS (ESI): m/z=392.2 [M+H]+;
elemental analysis: calcd (%) for C21H33N3O2S (391.55): C 64.41, H
8.50, N 10.73, S 8.19; found: C 64.15, H 8.77, N 10.60, S 8.13.
1-Cyano-7-(diphenylmethylidene)-1,3,5-cycloheptatriene
(5d):
Orange solid; m.p. 177–1798C (hexane); 1H NMR (CDCI3): d=5.97
(dd, JH5,H4 =6.6 Hz, JH5,H6 =11.1 Hz, 1H, H5), 6.27 (d, JH6,H5 =11.1 Hz,
1H, H6), 6.35 (dd, JH3,H2 =6.6 Hz, JH3,H4 =11.1 Hz, 1H, H3), 6.57 (dd,
J
H4,H5 =6.6 Hz, JH4,H3 =11.1 Hz, 1H, H4), 6.74 (d, JH2,H3 =6.6 Hz, 1H,
1
H2), 7.2–7.4 ppm (m, 10H, Ph); the assignment of H NMR signals
was supported by several homonuclear NOE experiments and
1 H,1H shift correlations (see the Supporting Information); 13C NMR
(CDCI3): d=112.20 (s, CN), 117.94 (s, C1), 127.01 (s), 127.16 (d, C5),
127.46 (d), 127.91 (d), 128.26 (d), 128.54 (d), 128.66 (d, C3), 129.12
(d), 129.18 (d), 132.77 (d, C6), 136.94 (d, C4), 139.69 (s), 140.19 (s),
141.10 (d, C2), 144.84 ppm (s); the assignment of 13C NMR signals
was supported by heteronuclear 13C,1H shift correlations; IR
(CDCI3): n˜ =3029 (s, CH), 2215 (CꢁN), 1601 cmÀ1 (m, C=C); HRMS
(ESI): m/z calcd for C21H16N ([M+H]+): 282.1277; found: 282.1260.
4-tert-Butyl-1-(2,4,6-triisopropylphenylsulfonyl)-1H-1,2,3-triazole
(16c): White solid; m.p. 138–1408C (CHCl3); 1H NMR (CDCI3): d=
1.19 (d, 3J=6.6 Hz, 12H, CH(CH3)2), 1.25 (d, 3J=7.0 Hz, 6H,
3
CH(CH3)2), 1.36 (s, 9H, C(CH3)3), 2.91 (sept, J=7.0 Hz, 1H, CH(CH3)2),
3
4.13 (sept, J=6.6 Hz, 2H, CH(CH3)2), 7.21 (s, 2H, CCHC), 7.90 ppm
(s, 1H, NCHC); in homonuclear NOE experiments, irradiation at the
frequency of the H5 atom indicated effects not only at the signal
of the tert-butyl group but also at that of the corresponding iso-
propyl group (Me group of 2,6-iPr; see Scheme 3); 13C NMR (CDCI3):
d=23.39 (q), 24.47 (q), 29.87 (d), 30.03 (q), 30.95 (s, C(CH3)3), 34.34
(d), 117.34 (d), 124.56 (d), 129.17 (s), 152.69 (s), 155.91 (s),
156.84 ppm (s); IR (CDCI3): n˜ =2965, 2934, 2872 (s, CH), 1598 (m,
C=C), 1184 cmÀ1 (s, SO2ÀN); MS (ESI): m/z=392.2 [M+H]+; elemen-
tal analysis: calcd (%) for C21H33N3O2S (391.55): C 64.41, H 8.50, N
10.73, S 8.19; found: C 64.15, H 8.77, N 10.60, S 8.13.
Synthesis of 5-cyano-2-(triphenylmethyl)-2H-tetrazole (19d)
In analogy with a known protocol,[23] sodium 5-cyanotetrazolate
sesquihydrate[24] (18d; 360 mg, 2.5 mmol) in water (10 mL) was
added to tetrabutylammonium bromide (64.5 mg, 0.2 mmol) in
chloroform (10 mL). A solution of triphenylmethyl chloride (0.84 g,
3 mmol) in chloroform (20 mL) was added, and the mixture was
stirred overnight at room temperature. The organic phase was sep-
arated, washed with 10% aqueous NaOH (5 mL) and twice with
water (210 mL), dried (MgSO4), and evaporated to dryness. The
residue was recrystallized from EtOAc to yield a white solid
5,7-Diisopropyl-3,3-dimethylbenz[d]-2,1-oxathiole 1-oxide (17):
White solid; m.p. 768C (CHCl3; ref. [20]: 75.0–76.58C); 1H NMR
(CDCI3): d=1.28 (d, 3J=7.0 Hz, 6H, CH(CH3)2), 1.36 (d, 3J=7.0 Hz,
6H, CH(CH3)2), 1.65 (s, 3H, OC(CH3)2), 1.85 (s, 3H, OC(CH3)2), 2.99
(sept, 3J=7.0 Hz, 1H, CH(CH3)2), 3.41 (sept, 3J=7.0 Hz, 1H,
1
(220 mg, 26%). M.p. 175–1768C; H NMR (CDCl3): d=7.04–7.10 (m,
5H, Ph), 7.33–7.42 ppm (m, 10H, Ph); 13C NMR (CDCl3): d=85.74 (s,
C(Ph)3), 109.15 (s, CN), 128.07 (d, Ph), 128.96 (d, Ph), 130.12 (d, Ph),
139.96 (s, iPh), 141.51 ppm (s, C5); IR (CCl4): n˜ =3063.9, 3029,
1751.5, 1549.1, 1448.1 cmÀ1; elemental analysis: calcd (%) for
C21H15N5 (337.26): C 74.76, H 4.48, N 20.76; found: C 74.21, H 4.50,
N 20.42.
4
4
CH(CH3)2), 6.93 (d, J=1.4 Hz, 1H, CHCCC(CH3)2), 7.20 ppm (d, J=
1.4 Hz, 1H, (CH3)2CHCCHCCH(CH3)2); our 1H NMR spectroscopic
data were identical with those in reference [20]; 13C NMR (CDCI3):
d=23.29 (q), 23.95 (q), 23.99 (q), 24.12 (q), 28.93 (q), 31.75 (d),
32.44 (q), 34.54 (d), 98.01 (s, OC(CH3)2), 117.10 (d), 124.50 (d),
142.41 (s), 146.16 (s), 146.44 (s), 154.53 ppm (s); IR (CDCI3): n˜ =
2966, 2932, 2872 (s, CH), 1137, 1105 cmÀ1 (s, S=O); MS (ESI): m/z=
267.2 [M+H]+.
Synthesis of 5-ethoxycarbonyl-2-(triphenylmethyl)-2H-tetra-
zole (19e)
As described for the synthesis of 19d, sodium tetrazolide 18e
(10 mmol, purchased from ABCR GmbH), tetrabutylammonium bro-
mide (0.8 mmol), and triphenylmethyl chloride (12 mmol) led to
19e (2.18 g, 57%) as a white solid. M.p. 166–1688C (ethyl acetate);
Reaction of tritylacetylene (15d) with butyllithium and trisyl
azide
3
3
1H NMR (CDCl3): d=1.43 (t, J=7.1 Hz, 3H, OCH2CH3), 4.50 (q, J=
7.1 Hz, 2H, OCH2CH3), 7.08–7.14 (m, 5H, Ph), 7.30–7.40 ppm (m,
10H, Ph); 13C NMR (CDCl3): d=14.12 (t, CH3), 62.50 (q, OCH2), 84,37
(s, C(Ph)3), 127.86 (d, Ph), 128.54 (d, Ph), 130.17 (d, Ph), 140.61 (s,
A solution of 15d[21] (408 mg, 1.52 mmol) in anhydrous THF
(10 mL) was treated with nBuLi at À458C and then with trisyl
Chem. Eur. J. 2015, 21, 14911 – 14923
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