FEATURE ARTICLE
Synthesis of Enantiomerically Pure Allenes with Central and Axial Chirality
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4.90 (m, 2 H), 4.62–4.58 (m, 2 H), 3.92–3.88 (m, 1 H), 2.50–2.38
(m, 1 H), 2.35 (s, 3 H), 2.30–1.95 (m, 1 H).
13C NMR (75 MHz, CDCl3): d = 208.2, 142.6, 142.2, 142.1, 141.7,
135.5, 131.2, 130.0, 127.9, 127.8, 126.3, 125.0, 116.8, 93.3, 77.3,
39.0, 38.8, 21.4.
IR (NaCl): 3058, 2923, 1684, 1117, 1032, 810, 758 cm–1.
1 H NMR (300 MHz, CDCl3): d = 8.06 (m, 1 H), 7.48–7.20 (m, 12
H), 5.12–5.07 (m, 1 H), 3.99–3.71 (m, 2 H), 2.38 (s, 3 H), 1.53 (d,
J = 7.0 Hz, 3 H).
13C NMR (75 MHz, CDCl3): d = 206.1, 143.1, 141.5, 137.2, 136.2,
131.6, 130.7, 130.1, 129.9, 128.3, 127.6, 126.6, 126.0, 125.8, 124.3,
103.6, 90.1, 32.9, 24.4, 13.8.
MS (FAB): m/z (%) = 309 ([M + H], 100), 271 (36), 211 (29).
HRMS: m/z [M + H+] calcd for C20H21OS: 309.1306; found:
309.1307.
HRMS: m/z [M + H+] calcd for C24H23OS: 359.1469; found:
359.1474.
Anal. Calcd for C20H20OS: C, 77.88; H, 6.54; S, 10.40. Found: C,
76.58; H, 6.63; S, 10.03.
(aR)-2-[(2R)-3-Phenylhexa-3,4-dien-2-yl]phenyl p-Tolyl
(S)-Sulfoxide (4n)
2-[(R)-3-Methylhepta-1,2,6-trien-4-yl]phenyl p-Tolyl (S)-Sulf-
oxide (4l)
Following the general procedure starting from sulfoxide 1d and
1-bromobut-2-yne (2c) with flash chromatography (toluene–
EtOAc, 20:1) gave 4l (75%) as a colorless oil; mixture of diastereo-
mers 95:5.
[a]D20 –200.6 (c 1.0, CHCl3).
IR (NaCl): 2966, 1957, 1716, 1594, 1083, 1030 cm–1.
Following the general procedure starting from sulfoxide 1b and (R)-
4-phenylbut-3-yn-2-yl mesylate [(R)-2g] with flash chromatogra-
phy (toluene–EtOAc, 20:1) gave 4n (88%) as a colorless oil; single
diastereomer. Starting from racemic 4-phenylbut-3-yn-2-yl mesy-
late (rac-2g) gave 4n (58%); 90% de [HPLC (2 Chiralpak OD col-
umns, hexane–i-PrOH, 95:5; flow rate 0.3 mL/min): tR = 94.3
(major), 106.2 (minor) min].
[a]D20 –45.7 (c 0.51, CHCl3).
1H NMR (300 MHz, CDCl3): d (major diastereomer) = 7.98–7.97
(m, 1 H), 7.52–7.24 (m, 7 H), 5.50–5.39 (m, 2 H), 5.00–4.95 (m, 2
H), 4.85–4.72 (m, 2 H), 3.65–3.60 (m, 1 H), 2.50–2.38 (m, 1 H),
2.38 (s, 3 H), 1.99–1.90 (m, 2 H), 1.60 (t, J = 3.1 Hz, 1 H); d (minor
diastereomer) = 7.98–7.97 (m, 1 H), 7.52–7.24 (m, 7 H), 5.50–5.39
(m, 2 H), 5.00–4.95 (m, 2 H), 4.85–4.72 (m, 2 H), 3.65–3.60 (m, 1
H), 2.50–2.38 (m, 1 H), 2.38 (s, 3 H), 1.99–1.90 (m, 2 H), 1.03 (t,
J = 3.1 Hz, 1 H).
IR (NaCl): 2970, 1682, 1594, 1449, 1029 cm–1.
1H NMR (300 MHz, CDCl3): d (major diastereomer) = 8.06 (d,
J = 7.0 Hz, 1 H), 7.38–6.80 (m, 12 H), 5.66–5.64 (m, 1 H), 4.35–
4.29 (m, 1 H), 2.39 (d, J = 6.0 Hz, 3 H), 2.38 (s, 3 H), 1.69 (d,
J = 7.0 Hz, 3 H); d (minor diastereomer) = 8.06 (d, J = 7.0 Hz, 1 H),
7.38–6.80 (m, 12 H), 5.48–5.46 (m, 1 H), 4.35–4.29 (m, 1 H), 2.38
(s, 3 H), 1.86 (d, J = 6.0 Hz, 3 H), 0.96 (d, J = 7.0 Hz, 3 H).
13C NMR (75 MHz, CDCl3): d = 205.8, 143.7, 142.0, 141.9, 136.3,
131.3, 130.1, 128.4, 128.0, 127.5, 127.3, 126.8, 126.6, 126.5, 124.5,
109.9, 90.9, 34.8, 21.9, 21.4, 14.2.
13C NMR (75 MHz, CDCl3): d = 206.4, 143.1, 141.9, 141.8, 136.0,
131.2, 130.0, 129.9, 127.7, 126.5, 126.4, 124.6, 116.2, 101.2, 76.7,
43.0, 38.4, 21.4, 18.2.
MS (ESI): m/z (%) = 373 ([M + H], 100), 349 (63), 301 (50), 259
(25), 234 (12), 139 (19).
HRMS: m/z [M + H+] calcd for C25H25OS: 373.1609; found:
373.1620.
MS (FAB): m/z (%) = 323 ([M + H+], 100), 322 (18), 321 (79), 311
(19).
HRMS: m/z [M + H+] calcd for C21H23OS: 323.1452; found:
323.1464.
Anal. Calcd for C21H22OS: C, 78.22; H, 6.88; S, 9.94. Found: C,
76.89; H, 7.07; S, 9.43.
(aS)-2-[(2R)-Hexa-3,4-dien-2-yl]phenyl p-Tolyl (S)-Sulfoxide
(4o)
Following the general procedure starting from sulfoxide 1b and rac-
but-3-yn-2-yl mesylate (rac-2h) with flash chromatography (tolu-
ene–EtOAc, 20:1) gave 4o (53%) as a colorless oil; mixture of dia-
stereomers 90:10.
[a]D20 –191.0 (c 1.85, CHCl3).
1H NMR (300 MHz, CDCl3): d (major diastereomer) = 7.90–7.88
(m, 1 H), 7.42–7.15 (m, 7 H), 5.16–5.13 (m, 2 H), 3.86–3.81 (m, 1
H), 2.28 (s, 3 H), 1.63–1.55 (m, 6 H).
(aR)-2-(2-Phenylpenta-2,3-dienyl)phenyl p-Tolyl (S)-Sulfoxide
(4m)
Following the general procedure starting from sulfoxide 1a and (R)-
4-phenylbut-3-yn-2-yl mesylate [(R)-2g] with flash chromatogra-
phy (toluene–EtOAc, 20:1) gave 4m (76%) as a colorless oil; single
diastereomer.
[a]D20 –75.0 (c 0.9, CH2Cl2).
IR (NaCl): 3058, 2920, 1684, 1117, 1032, 810, 758 cm–1.
13C NMR (75 MHz, CDCl3): d = 204.1, 144.3, 142.4, 141.7, 131.3,
130.0, 127.9, 127.8, 127.5, 126.1, 124.6, 95.5, 88.5, 33.8, 21.4,
14.6, 14.2.
1H NMR (300 MHz, CDCl3): d = 8.06 (m, 1 H), 7.48–7.20 (m, 12
H), 5.45–5.40 (m, 1 H), 3.99–3.71 (m, 2 H), 2.38 (s, 3 H), 1.60 (d,
J = 7.0 Hz, 3 H).
13C NMR (75 MHz, CDCl3): d = 206.0, 143.2, 141.6, 137.3, 136.2,
131.6, 130.8, 130.2, 129.9, 128.3, 127.7, 126.7, 126.1, 125.9, 124.6,
103.1, 90.0, 32.8, 21.4, 13.7.
HRMS: m/z [M + H+] calcd for C24H23OS: 359.1469; found:
359.1478.
(aR)-(2-[(2R)-3-(4-Bromophenyl)hexa-3,4-dien-2-yl]phenyl
p-Tolyl (S)-Sulfoxide (4p)
Following the general procedure starting from sulfoxide 1b and rac-
4-(4-bromophenyl)but-3-yn-2-yl mesylate (rac-2i) with flash chro-
matography (toluene–EtOAc, 20:1) gave 4p (56%) as a colorless
oil; mixture of diastereomers 85:15.
[a]D20 –93.9 (c 2.08, CHCl3).
(aS)-2-(2-Phenylpenta-2,3-dienyl)phenyl p-Tolyl (S)-Sulfoxide
(4m¢)
Following the general procedure starting from sulfoxide 1a and (S)-
4-phenylbut-3-yn-2-yl mesylate [(S)-2g] with flash chromatogra-
phy (toluene–EtOAc, 20:1) gave 4m¢ (73%) as a colorless oil; single
diastereomer.
IR (NaCl): 2973, 2925, 1628, 1595, 1491, 1083, 1054, 1030 1469,
758 cm–1.
1H NMR (300 MHz, CDCl3): d (major diastereomer) = 7.92–6.99
(m, 12 H), 5.63–5.60 (m, 1 H), 4.33–4.27 (m, 1 H), 2.38 (s, 3 H),
1.77 (d, J = 7.0 Hz, 3 H), 0.87 (d, J = 7.0 Hz, 3 H); d (minor diaste-
reomer) = 7.92–6.99 (m, 14 H), 5.53–5.46 (m, 1 H), 4.23–4.17 (m,
[a]D20 –84.5 (c 1.1, CH2Cl2).
Synthesis 2009, No. 19, 3339–3349 © Thieme Stuttgart · New York