Birch Reduction – Reactivity of Arylphosphorus Acid Amides
0.5 mmol) and sodium (0.029 g, 1.25 mmol), yield 32% (based on
(m, 1 H), 2.88–3.03 (m, 1 H), 3.04–3.18 (m, 4 H), 3.35 (s, 3 H),
3.90–4.00 (m, 1 H), 4.73–4.77 (m, 1 H), 5.62–5.68 (m, 1 H), 5.89–
NMR analysis). Isolated as a mixture with starting material and
1
26c. RF = 0.43 (hexane/EtOAc 6:1). H NMR (500 MHz, CDCl3): 5.95 (m, 1 H), 7.23–7.28 (m, 2 H), 7.67–7.72 (m, 2 H) ppm. 13C
δ = 0.37–1.11 (br. m, 3 H), 1.08 (t, JH,H = 6.9 Hz, 6 H), 2.72–2.81
NMR (126 MHz, CDCl3): δ = 14.28 (d, JP,C = 1.8 Hz), 21.49, 26.73
(m, 2 H), 3.16–3.25 (m, 4 H), 3.88 (s, 3 H), 4.15–4.25 (m, 1 H), (d, JP,C = 4.5 Hz), 39.09 (d, JP,C = 32.7 Hz), 41.55 (d, JP,C = 1.8 Hz),
5.60–5.67 (m, 1 H), 5.73–5.78 (m, 1 H), 5.80–5.89 (m, 2 H), 6.93–
6.97 (m, 1 H), 7.02–7.07 (m, 1 H), 7.43–7.46 (m, 1 H), 7.62–7.66
52.80, 93.64 (d, JP,C = 6.4 Hz), 121.55 (d, JP,C = 4.5 Hz), 128.41 (d,
JP,C = 10.0 Hz), 129.61, 131.56 (d, JP,C = 9.1 Hz), 140.50 (d, JP,C
=
(m, 1 H) ppm. 13C NMR (126 MHz, CDCl3): δ = 14.36 (d, JP,C
=
1.8 Hz), 150.97 (d, JP,C = 3.6 Hz) ppm. 31P NMR (202 MHz,
CDCl3): δ = 74.08 (br. m) ppm.
1.8 Hz), 26.53 (d, JP,C = 5.5 Hz), 37.80 (d, JP,C = 40.9 Hz), 41.63
(d, JP,C = 1.8 Hz), 55.38, 111.17 (d, JP,C = 5.5 Hz), 120.07 (d, JP,C
= 49.1 Hz), 121.08 (d, JP,C = 10.0 Hz), 123.01 (d, JP,C = 7.3 Hz),
126.35 (d, JP,C = 8.2 Hz), 132.52 (d, JP,C = 1.8 Hz), 133.99 (d, JP,C
= 8.2 Hz), 160.21 (d, JP,C = 4.5 Hz) ppm. 31P NMR (202 MHz,
CDCl3): δ = 75.33 (br. m) ppm.
o-Anisyl-(2-methyl-1,4-dihydronaphth-1-yl)phosphinous Acid–Bor-
ane N,N-Diethylamide (23e): This compound was obtained by the
General Procedure from 9e (0.183 g, 0.5 mmol) and sodium
(0.029 g, 1.25 mmol) as a mixture with 26e and starting material,
yield 72% (based on NMR analysis) as a mixture of two dia-
stereomers in 70% de ratio. RF = 0.44 (hexane/EtOAc 6:1).
(2-Methoxycyclohexa-1,4-dien-3-yl)phenylphosphinous Acid–Borane
N,N-Diethylamide (23cЈ): This compound was prepared from 9c
(0.150 g, 0.5 mmol) and sodium (0.029 g, 1.25 mmol), yield 0.039 g
(26%). Isolated as a mixture of two diastereomers in 66% de ratio.
Colourless oil. RF = 0.38 (hexane/EtOAc 6:1).
1
Major Diastereomer: H NMR (500 MHz, CDCl3): δ = 0.23–1.02
(br. m, 3 H), 0.73 (t, JH,H = 6.9 Hz, 6 H), 1.45–1.48 (m, 3 H), 2.84–
2.93 (m, 2 H), 3.17–3.27 (m, 3 H), 3.87–3.99 (m, 1 H), 4.02 (s, 3
H), 5.11–5.19 (m, 1 H), 5.78–5.84 (m, 1 H), 6.94–7.00 (m, 1 H),
7.05–7.10 (m, 1 H), 7.12–7.22 (m, 4 H), 7.49–7.53 (m, 1 H), 8.11–
8.17 (m, 1 H) ppm. 13C NMR (126 MHz, CDCl3): δ = 14.19 (d,
1
Major Diastereomer: H NMR (500 MHz, CDCl3): δ = 0.34–1.09
(br. m, 3 H), 0.98 (t, JH,H = 7.3 Hz, 6 H), 2.80–2.88 (m, 1 H), 2.91–
2.99 (m, 1 H), 3.05–3.18 (m, 4 H), 3.46 (s, 3 H), 3.91–3.99 (m, 1
H), 4.79–4.82 (m, 1 H), 5.60–5.65 (m, 1 H), 5.86–5.91 (m, 1 H),
7.38–7.46 (m, 3 H), 7.75–7.80 (m, 2 H) ppm. 13C NMR (126 MHz,
CDCl3): δ = 14.54 (d, JP,C = 1.8 Hz), 26.74 (d, JP,C = 4.5 Hz), 38.75
JP,C = 1.8 Hz), 22.87, 32.31 (d, JP,C = 3.6 Hz), 42.85 (d, JP,C
=
1.8 Hz), 46.52 (d, JP,C = 30.9 Hz), 54.82, 110.42 (d, JP,C = 3.6 Hz),
121.30 (d, JP,C = 11.8 Hz), 124.90 (d, JP,C = 2.7 Hz), 125.95 (d, JP,C
= 10.0 Hz), 126.31 (d, JP,C = 2.7 Hz), 127.97 (d, JP,C = 2.7 Hz),
129.44 (d, JP,C = 3.6 Hz), 130.62, 133.22 (d, JP,C = 1.8 Hz), 133.40
(d, JP,C = 32.7 Hz), 41.70 (d, JP,C = 2.7 Hz), 53.84, 94.06 (d, JP,C
6.4 Hz), 121.48 (d, JP,C = 1.8 Hz), 128.08 (d, JP,C = 9.1 Hz), 128.46
(d, JP,C = 10.0 Hz), 130.34 (d, JP,C = 1.8 Hz), 131.38 (d, JP,C
=
(d, JP,C = 2.7 Hz), 136.49 (d, JP,C = 16.4 Hz), 137.81 (d, JP,C
=
4.5 Hz), 160.68 (d, JP,C = 1.8 Hz) ppm. 31P NMR (202 MHz,
CDCl3): δ = 77.41 (br. m) ppm.
=
9.1 Hz), 132.77 (d, JP,C = 60.0 Hz), 151.11 (d, JP,C = 6.4 Hz) ppm.
31P NMR (202 MHz, CDCl3): δ = 73.40 (br. m) ppm.
1
Minor Diastereomer: H NMR (500 MHz, CDCl3): δ = 0.23–1.02
1
Minor Diastereomer: H NMR (500 MHz, CDCl3): δ = 0.34–1.09
(br. m, 3 H), 0.96 (t, JH,H = 6.9 Hz, 6 H), 2.00–2.02 (m, 3 H), 3.08–
3.17 (m, 3 H), 3.29–3.36 (m, 1 H), 3.41–3.49 (m, 2 H), 4.05 (s, 3
H), 5.08–5.15 (m, 1 H), 5.98–6.02 (m, 1 H), 6.91–6.95 (m, 1 H),
6.99–7.04 (m, 1 H), 7.12–7.22 (m, 4 H), 7.42–7.49 (m, 1 H), 7.81–
7.86 (m, 1 H) ppm. 13C NMR (126 MHz, CDCl3): δ = 13.91 (d,
(br. m, 3 H), 1.07 (t, JH,H = 6.9 Hz, 6 H), 2.76–2.83 (m, 1 H), 2.97–
3.05 (m, 1 H), 3.05–3.18 (m, 4 H), 3.33 (s, 3 H), 3.95–4.03 (m, 1
H), 4.74–4.77 (m, 1 H), 5.63–5.68 (m, 1 H), 5.91–5.97 (m, 1 H),
7.44–7.52 (m, 3 H), 7.78–7.84 (m, 2 H) ppm. 13C NMR (126 MHz,
CDCl3): δ = 14.23 (d, JP,C = 1.8 Hz), 26.71 (d, JP,C = 4.5 Hz), 38.94
JP,C = 1.8 Hz), 24.07, 32.40 (d, JP,C = 3.6 Hz), 42.56 (d, JP,C
=
(d, JP,C = 32.7 Hz), 41.55 (d, JP,C = 2.7 Hz), 53.76, 93.73 (d, JP,C
6.4 Hz), 121.36 (d, JP,C = 4.5 Hz), 127.76 (d, JP,C = 10.0 Hz), 128.32
(d, JP,C = 9.1 Hz), 130.27 (d, JP,C = 2.7 Hz), 131.49 (d, JP,C
9.1 Hz), 133.32 (d, JP,C = 57.2 Hz), 150.77 (d, JP,C = 3.6 Hz) ppm.
31P NMR (202 MHz, CDCl3):
74.61 (br. m) ppm.
=
1.8 Hz), 45.40 (d, JP,C = 34.5 Hz), 54.84, 110.16 (d, JP,C = 4.5 Hz),
121.47 (d, JP,C = 12.7 Hz), 124.59 (d, JP,C = 3.6 Hz), 125.79 (d, JP,C
= 9.1 Hz), 126.05 (d, JP,C = 3.6 Hz), 128.00 (d, JP,C = 2.7 Hz),
131.22 (d, JP,C = 4.5 Hz), 130.45, 132.97 (d, JP,C = 1.8 Hz), 132.75
=
δ
=
(d, JP,C = 2.7 Hz), 136.68 (d, JP,C = 14.5 Hz), 137.80 (d, JP,C
=
4.5 Hz), 160.21 (d, JP,C = 1.8 Hz) ppm. 31P NMR (202 MHz,
CDCl3): δ = 79.59 (br. m) ppm.
C17H27BNOP (303.19): calcd. C 67.35, H 8.98, N 4.62; found C
67.59, H 9.15, N 4.60.
(2-Methoxycyclohexa-1,4-dien-3-yl)(o-tolyl)phosphinous Acid–Bor-
ane N,N-Diethylamide (23d): This compound was obtained by the
General Procedure from 9d (0.158 g, 0.5 mmol) and sodium
(0.029 g, 1.25 mmol) as a mixture with 26d, yield 41% (based on
NMR analysis) as a mixture of two diastereomers in 54% de ratio.
RF = 0.58 (hexane/EtOAc 6:1).
tert-Butyl(cyclohexa-1,4-dien-3-yl)phosphinic Acid N,N-Diethyl-
amide (24a): This compound was prepared from 10a (0.127 g,
0.5 mmol) and sodium (0.029 g, 1.25 mmol), yield 0.121 g (95%).
Colourless oil. RF
=
0.79 (CHCl3/MeOH 15:1). 1H NMR
(400 MHz, CDCl3): δ = 0.99 (d, JH,H = 7.1 Hz, 6 H), 1.12 (d, JP,H
= 14.7 Hz, 9 H), 2.60–2.71 (m, 2 H), 2.96–3.12 (m, 4 H), 3.45–3.58
(m, 1 H), 5.71–5.84 (m, 4 H) ppm. 13C NMR (75 MHz, CDCl3): δ
= 14.05 (d, JP,C = 1.72 Hz), 25.59 (d, JP,C = 92.53 Hz), 25.85, 38.40
1
Major Diastereomer: H NMR (500 MHz, CDCl3): δ = 0.30–1.05
(br. m, 3 H), 0.96 (t, JH,H = 7.1 Hz, 6 H), 2.39 (s, 3 H), 2.74–2.87
(m, 1 H), 2.88–3.03 (m, 1 H), 3.04–3.18 (m, 4 H), 3.48 (s, 3 H),
3.90–4.00 (m, 1 H), 4.79–4.83 (m, 1 H), 5.56–5.62 (m, 1 H), 5.83–
5.89 (m, 1 H), 7.23–7.28 (m, 2 H), 7.64–7.69 (m, 2 H) ppm. 13C
NMR (126 MHz, CDCl3): δ = 14.59 (d, JP,C = 1.8 Hz), 21.41, 26.75
(d, JP,C = 4.5 Hz), 38.65 (d, JP,C = 32.7 Hz), 41.70 (d, JP,C = 2.7 Hz),
53.88, 94.03 (d, JP,C = 6.4 Hz), 121.60 (d, JP,C = 1.8 Hz), 127.55 (d,
JP,C = 65.4 Hz), 128.91 (d, JP,C = 10.0 Hz), 129.52, 131.47 (d, JP,C
= 9.1 Hz), 140.65 (d, JP,C = 2.7 Hz), 151.22 (d, JP,C = 6.4 Hz) ppm.
31P NMR (202 MHz, CDCl3): δ = 72.86 (br. m) ppm.
(d, JP,C = 3.16 Hz), 39.34 (d, JP,C = 104.31 Hz), 39.57 (d, JP,C
=
3.74 Hz), 121.69 (d, JP,C = 7.47 Hz), 122.02 (d, JP,C = 6.32 Hz),
126.71 (d, JP,C = 8.91 Hz), 126.93 (d, JP,C = 8.91 Hz) ppm. 31P
NMR (162 MHz, CDCl3): δ = 51.43 ppm. C14H26NOP (255.34):
calcd. C 65.85, H 10.26, N 5.49; found C 65.80, H 10.50, N 5.66.
Benzyl(cyclohexa-1,4-dien-3-yl)phosphinic Acid N,N-Diethylamide
(24b): This compound was prepared from 10b (0.144 g, 0.5 mmol)
and sodium (0.029 g, 1.25 mmol), yield 0.125 g (86%). White solid,
m.p. 89.3–91.1 °C. RF = 0.48 (CHCl3/MeOH 15:1). 1H NMR
(500 MHz, CDCl3): δ = 0.90 (t, JH,H = 6.9 Hz, 6 H), 2.73–2.83 (m,
2 H), 2.98–3.08 (m, 4 H), 3.12–3.20 (m, 1 H), 3.25–3.33 (m, 1 H),
Minor Diastereomer: 1H NMR (500 MHz, CDCl3): δ = 0.06–1.5
(br. m, 3 H), 0.97 (t, JH,H = 7.1 Hz, 6 H), 2.39 (s, 3 H), 2.74–2.87
Eur. J. Org. Chem. 2013, 4351–4371
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
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