10.1002/ejoc.202001065
European Journal of Organic Chemistry
FULL PAPER
1H, CH), 7.51-7.58 (m, 2H, ArH), 7.60-7.68 (m, 1H, ArH), 7.83-7.92 (m,
2H, ArH) ppm. E-30: = 1.64-1.70 (m, 3H, CH3), 3.73 (d, J = 7.0 Hz, 2H,
(400 MHz, CDCl3):
4.76 (tt, J = 7.5, 1.0 Hz, 1H, CH), 7.07-7.12 (m, 2H, ArH), 7.24-7.34 (m,
δ
= 3.55 (s(br), 2H, CH2), 3.92 (d, J = 7.5 Hz, 2H, CH2),
δ
CH2), 5.37-5.48 (m, 1H, CH), 5.50-5.61 (m, 1H, CH), 7.51-7.58 (m, 2H,
ArH), 7.60-7.68 (m, 1H, ArH), 7.83-7.92 (m, 2H, ArH) ppm. Data as
reported.[28]
3H, ArH), 7.49-7.55 (m, 2H, ArH), 7.61-7.66 (m, 1H, ArH), 7.85-7.90 (m,
2H, ArH) ppm. 13C-NMR (100 MHz, CDCl3):
δ = 39.3 (CH2), 54.6 (CH2),
103.6 (CH), 127.5 (CH), 128.6 (CH), 128.8 (CH), 129.0 (2xCH), 133.8 (CH),
135.3 (C), 138.8 (C), 142.1 (C) ppm.
Method D (“one-pot”): Phosphonate 17 (277 mg, 0.95 mmol, 1.1 equiv.),
propanal 18 (50 mg, 0.862 mmol, 1.0 equiv.) and DBU (393 mg, 2.56 mmol,
3.0 equiv.) were stirred in MeCN (8 mL) at room temperature for 18 h. The
mixture was diluted with water (10 mL) and extracted with EtOAc (3 x 15
mL). The combined organic layers were washed with 1 M HCl (50 mL),
brine (50 mL) and dried over MgSO4. Solvent was removed in vacuo to
give crude product as a viscous yellow oil (179 mg). Purification by column
chromatography (c-Hex:EtOAc, 6:1) yielded allyl sulfone 30 (149 mg, 88%)
as a colourless oil with an E:Z ratio of 30:70. Data as above.
(Z)-[(3-Azido-4-methylpent-2-en-1-yl)sulfonyl]benzene 44:
In an
identical procedure used to prepare vinyl azide 41 above, allyl bromide 37
(82 mg, 0.27 mmol, 1.0 equiv.) and NaN3 (71 mg, 1.08 mmol, 4.0 equiv.)
were stirred in MeCN (5 mL) for 120 h at room temperature. The mixture
was then heated to reflux for 48 h. The solution was then cooled to room
temperature and DBU (41 mg, 0.27 mmol, 1.0 equiv.) was added before
the mixture was stirred at room temperature for 1 h. This yielded vinyl
azide 44 (35 mg, 49%) as a pale yellow solid-oil mixture, with an E:Z ratio
of 5:95. Rf = 0.35 (c-Hex:EtOAc, 6:1). IR (neat): 3065, 2933, 2876, 2108,
1650, 1390, 1361, 999, 774, 563 cm-1. HRMS (ES+): C12H15N3O2SNa
(E/Z)-[(3-Azidobut-2-en-1-yl)sulfonyl]benzene 43: Allyl bromide 36
(175 mg, 0.64 mmol, 1.0 equiv.) and sodium azide (83 mg, 1.27 mmol, 2.0
equiv.) were stirred in MeCN (7 mL) at room temperature for 72 h. DBU
(97 mg, 0.64 mmol, 1.0 equiv.) was then added and stirring was continued
for 1 h. The mixture was diluted with water (10 mL) and extracted with
EtOAc (3 x 20 mL). The combined organic layers were washed with 1 M
HCl (60 mL) and brine (60 mL), dried over MgSO4 and solvent was
removed in vacuo to yield vinyl azide 43 (112 mg, 75%) as a light brown
solid, with an E:Z ratio of 15:85 and without the need for further purification.
Rf = 0.30 (c-Hex:EtOAc, 6:1). HRMS (ES+): C10H11N3O2SNa (MNa+) calcd.
(MNa+) calcd. 288.0777; found 288.0778. 1H NMR (400 MHz, CDCl3):
1.05 (d, J = 7.0 Hz, 6H CH3), 2.38 (hept, J = 7.0 Hz, 1H, CH), 3.86-3.89
δ =
(m, 2H, CH2), 4.71-4.78 (m, 1H, CH), 7.47-7.69 (m, 3H, ArH), 7.83-7.91
(m, 2H, ArH) ppm. 13C NMR (100 MHz, CDCl3):
δ = 20.9 (CH3), 31.3 (CH),
54.4 (CH2), 99.3 (CH), 128.7 (CH), 128.8 (CH), 133.8 (CH), 138.7 (C),
149.0 (C) ppm.
(Z)-[(3-Azido-2-methylallyl)sulfonyl]benzene 50:
In an identical
procedure to that described for the preparation of vinyl azide 10 (Method
B), (E)-[(3-bromo-2-methylprop-1-en-1-yl)sulfonyl]benzene (62 mg, 0.225
mmol, 1.0 equiv.), NaN3 (30 mg, 0.451 mmol, 2.0 equiv.) and DBU (34 mg,
0.225 mmol, 1.0 equiv.) were reacted to afford crude vinyl azide 50 (47
mg). Further purification by column chromatography (c-Hex:EtOAc, 8:1)
allowed isolation of (Z)-vinyl azide 50 (33 mg, 62%) as a white crystalline
solid. M.p. = 42-44 ˚C. X-Ray quality crystals were grown by gradual
evaporation of a solution of 50 in a minimum amount of DCM. Rf = 0.30 (c-
Hex:EtOAc, 8:1). IR (neat): 3063, 2919, 2109, 1650, 1383, 1301, 998, 746,
687, 580. HRMS (ES+): C10H11N3O2SNa (MNa+) calcd. 260.0464; found
260.0464; found 260.0464. 1H-NMR (400 MHz): E-43:
δ = 1.95 (q, J = 1.0
Hz, 3H, CH3), 3.85 (dd, J = 7.5, 1.0 Hz, 2H, CH2), 4.75 (tq, J = 7.5, 1.0 Hz,
1H, CH), 7.51-7.61 (m, 2H, ArH), 7.59-7.74 (m, 1H, ArH), 7.83-7.95 (m,
2H, ArH) ppm. 1H-NMR (400 MHz): Z-43:
δ = 1.58 (s, 3H, CH3), 3.77-3.87
(m, 2H, CH2), 4.96-5.08 (m, 1H, CH), 7.51-7.61 (m, 2H, ArH), 7.59-7.74
(m, 1H, ArH), 7.83-7.95 (m, 2H, ArH) ppm. 13C-NMR* (100 MHz, CDCl3):
δ
= 18.2 (CH3), 54.4 (CH2), 101.7 (CH), 128.4 (CH), 128.8 (CH), 133.7
(CH), 138.7 (C), 139.4 (C) ppm. *Data quoted for major Z-isomer only.
260.0466. 1H-NMR (400 MHz, CDCl3):
δ = 1.87 (d, J = 1.5 Hz, 3H, CH3),
(E/Z)-[(3-Azidonon-2-en-1-yl)sulfonyl]benzene 44: As described above
for the synthesis of vinyl azide 43, allyl bromide 37 (193 mg, 0.56 mmol,
1.0 equiv.) and NaN3 (145 mg, 2.24 mmol, 4.0 equiv.) in MeCN (10 mL)
were stirred and heated to reflux for 22 h. On cooling DBU (85 mg, 0.56
mmol, 1.0 equiv.) was added and the mixture was further stirred at room
temperature for 1 h. Work up and purification by flash chromatography (c-
Hex:EtOAc, 8:1) yielded vinyl azide 44 (79 mg, 51%) as a pale yellow oil,
with an E:Z ratio of 10:90. Rf = 0.30 (c-Hex:EtOAc, 8:1). IR (neat): 2955,
2928, 2858, 2110, 1656, 1447, 1305, 1144, 1084, 687 cm-1. HRMS (ES+):
C15H21N3O2SNa (MNa+) calcd. 330.1252; found 330.1246. 1H-NMR* (400
3.86 (s, 2H, CH2), 6.10 (app. d, J = 1.5 Hz, 1H, CH), 7.52-7.59 (m, 2H,
ArH), 7.63-7.69 (m, 1H, ArH), 7.89-7.94 (m, 2H, ArH) ppm. 13C-NMR (100
MHz, CDCl3):
δ = 19.7 (CH3), 57.9 (CH2), 114.8 (C), 127.8 (CH), 128.8
(CH), 128.9 (CH), 133.9 (CH), 128.9 (C) ppm.
(E/Z)-[(4-Azidobut-3-en-2-yl)sulfonyl]benzene 53: Allyl bromide 52 was
converted to [(4-azidobut-2-en-2-yl)sulfonyl]benzene 53 in an identical
manner to allyl azide 10 described above. Allyl bromide 52 (126 mg, 0.458
mmol, 1.0 equiv.), sodium azide (60 mg, 0.916 mmol, 2.0 equiv.) were
reacted together to afford (E)-[(4-azidobut-2-en-2-yl)sulfonyl]benzene
(109 mg, 0.459 mmol, 1.0 equiv.) which was dissolved in MeCN (5 mL).
DBU (70 mg, 0.459 mmol, 1.0 equiv.) was then added at room temperature
and stirring was continued for 0.5 h. The reaction mixture was diluted with
H2O (5 mL) and extracted with EtOAc (3 x 10 mL). The combined organic
layers were washed with brine (30 mL), dried over MgSO4, filtered and
solvent was removed in vacuo to give crude vinyl azide 53 (70 mg).
Purification by column chromatography (c-Hex:EtOAc, 6:1 to 4:1) afforded
vinyl azide 53 (46 mg, 42%) as a colourless viscous oil with an E:Z ratio of
80:20. Rf = 0.10 (c-Hex:EtOAc, 6:1). IR (neat): 3065, 2937, 2103, 1645,
1447, 1140, 999, 933, 726, 689 cm-1. HRMS (ES+): C10H11N3O2S (MNa+)
MHz, CDCl3):
δ = 0.85-0.91 (m, 3H, CH3), 1.13-1.46 (m, 8H, CH2), 2.12-
2.21 (m, 2H, CH2), 3.86 (d, J = 7.5 Hz, 2H, CH2), 4.68-4.77 (m, 1H, CH),
7.49-7.58 (m, 2H, ArH), 7.59-7.68 (m, 1H, ArH), 7.83-7.92 (m, 2H, ArH)
ppm. 13C-NMR* (100 MHz, CDCl3):
δ = 14.1 (CH3), 22.6 (CH2), 27.4 (CH2),
28.6 (CH2), 31.5 (CH2), 32.5 (CH2), 54.3 (CH2), 101.4 (CH), 128.6 (CH),
128.8 (CH), 133.8 (CH), 138.8 (C), 143.6 (C) ppm. *Data quoted for major
Z-isomer only.
(Z)-[2-Azido-4-(phenylsulfonyl)but-2-en-1-yl]benzene
45:
As
described above for the synthesis of vinyl azide 43, allyl bromide 38 (237
mg, 0.68 mmol, 1.0 equiv.) and NaN3 (175 mg, 2.70 mmol, 4.0 equiv.) in
MeCN (15 mL) were heated to reflux with stirring for 23 h. The mixture
was then cooled to room temperature and DBU (119 mg, 0.68 mmol, 1.0
equiv.) was added. The mixture was further stirred at room temperature
calcd. 260.0470; found 260.0482. 1H-NMR (400 MHz, CDCl3): E-53:
1.43 (d, J = 7.0 Hz, 3H, CH3), 3.62-3.74 (m, 1H, CH), 5.22 (dd, J = 13.5,
8.5 Hz, 1H, CH), 5.98 (d, J = 13.5 Hz, 1H, CH), 7.54-7.60 (m, 2H, ArH),
δ =
7.64-7.69 (m, 1H, ArH), 7.82-7.86 (m, 2H, ArH) ppm. Z-53:
δ = 1.43 (d, J
for
1 h. Work up as described and purification by flash column
= 7.0 Hz, 3H, CH3), 4.07-4.17 (m, 1H, CH), 4.78 (dd, J = 10.0, 7.5 Hz, 1H,
CH), 6.27 (d, J = 7.5 Hz, 1H, CH), 7.54-7.60 (m, 2H, ArH), 7.64-7.69 (m,
chromatography (c-Hex:EtOAc, 6:1) gave vinyl azide 45 (80 mg, 41%) as
a light brown oil (E:Z ratio of 5:95). Rf = 0.30 (c-Hex:EtOAc, 6:1). IR (neat):
3062, 3029, 2920, 2116, 1656, 1446, 1304, 1141, 1082, 686 cm-1. HRMS
(ES+): C16H15N3O2SNa (MNa+) calcd. 336.0783; found 336.0785. 1H-NMR
1H, ArH), 7.82 – 7.86 (m, 2H, ArH) ppm. 13C-NMR* (100 MHz, CDCl3):
δ
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