Dalton Transactions
Paper
3
3
3
(d, JPC = 4, Ar trans), 116.4 (d, JPC = 3, Ar cis), 114.4 (t, JPC
=
31P{1H} NMR (162 MHz, CDCl3): δ 143.7 (br, fwhm = 175 Hz).
HR ESI-MS (positive ion, 4 kV): 531.3840, [M + Na]+ (calcd
3
1
3, Ar{2-CH} trans), 113.3 (t, JPC = 4, Ar{2-CH} cis), 32.8 (d, JPC
= 37, tBu{C} cis), 32.7 (d, JPC = 38, tBu{C} trans), 32.10 (s, 531.3844) m/z.28
1
2
C̲
H2CHvCH trans), 32.06 (s, C
H2CHvCH cis), 31.6 (d, JPC
=
Anal. Calcd for C28H56B2O2P2 (508.32 g mol−1): C, 66.16; H,
13, CH2 trans), 31.2 (d, JPC = 13, CH2 cis), 28.8 (s, CH2 trans), 11.10; found: C, 66.09; H, 11.26.28
2
28.7 (s, CH2 cis), 28.1 (s, CH2 trans), 27.9 (s, CH2 cis), 25.5 (d,
Preparation of POCOP-14′. A solution of trans-12 (231 mg,
1JPC = 33, PCH2 cis), 25.4 (d, 1JPC = 33, PCH2 trans), 24.9 (d, 2JPC 455 μmol) in Et2NH (7 mL) was heated at 60 °C for 2 days.
2
= 3, tBu{CH3} cis), 24.8 (d, JPC = 3, tBu{CH3} trans), 23.0 (d, Volatiles were removed in vacuo to afford POCOP-14′ as a col-
3
3JPC = 2, CH2 trans), 22.7 (d, JPC = 2, CH2 cis). Data for major ourless oil. Yield: 217 mg (>99%).
alkene isomer only.
1H NMR (500 MHz, toluene-d8): δ 7.30 (app p, J = 2, 1H, Ar
31P{1H} NMR (162 MHz, CDCl3): δ 142.0–144.6 (br m).
{2-CH}), 6.97 (t, JHH = 8.1, 1H, Ar), 6.87 (app dt, JHH = 8.2, J =
3
3
HR ESI-MS (positive ion, 4 kV): 529.3689, [M + Na]+ (calcd 2, 2H, Ar), 1.84 (dtd, JHH = 14.4, JHH = 7.3, JPH = 3.2, 2H,
2
3
2
529.3687) m/z.
Preparation of 12. A suspension of [Rh(PPh3)3Cl] (201 mg, (d, 3JPH = 12.1, 18H, tBu).
220 μmol, 5 mol%) in benzene (20 mL) was added to a stirred
13C{1H} NMR (126 MHz, toluene-d8): δ 160.9 (d, JPC = 9, Ar
PCH2), 1.54–1.67 (m, 4H, CH2), 1.15–1.50 (m, 22H, CH2), 1.00
2
3
3
solution of 11 (2.20 g, 4.34 mmol) in benzene. The suspension {C}), 129.9 (s, Ar), 112.2 (d, JPC = 11, Ar), 109.2 (t, JPC = 12, Ar
was freeze–pump–thaw degassed and placed under a hydrogen {2-CH}), 32.5 (d, 1JPC = 16, tBu{C}), 31.1 (d, 2JPC = 11, CH2), 29.0
atmosphere and the resulting solution stirred at 50 °C for 2 (d, JPC = 24, PCH2), 28.9 (s, CH2), 28.5 (s, CH2), 28.2 (s, CH2),
1
3
2
days. Volatiles were removed under reduced pressure and the 28.0 (s, CH2), 25.5 (d, JPC = 15, CH2), 25.3 (d, JPC = 15, tBu
crude mixture was eluted through a short silica plug in air (5% {CH3}).
EtOAc in hexane) to afford 12 as a mixture of diastereomers
31P{1H} NMR (162 MHz, toluene-d8): δ 141.6 (s).
(2.02 g, 3.97 mmol, 92%). Subsequent purification by repeated
Preparation of the cis-diastereoisomer of POCOP-14′. A solu-
flash column chromatography in air (silica, 5% EtOAc in tion of cis-12 (10.0 mg, 19.7 μmol) in Et2NH (0.5 mL) was
hexane) enabled separation of the cis- and trans-diastereomers. heated at 80 °C for 2 days. Volatiles were removed in vacuo to
POCOP-14′·2BH3 (trans-12, Rf = 0.45). Yield: 951 mg (43%, afford the cis-diastereoisomer of POCOP-14′ as a colourless oil.
colourless oil which slowly crystallised upon standing).
Yield: 9.4 mg (>99%).
3
1H NMR (600 MHz, CDCl3): δ 7.19 (t, JHH = 8.2, 1H, Ar),
1H NMR (500 MHz, toluene-d8): δ 7.21 (app p, J = 2, 1H, Ar
{2-CH}), 6.97 (t, 3JHH = 7.9, 1H, Ar), 6.91 (app dt, 3JHH = 7.9, J =
4
3
4
7.03 (t, JHH = 2.5, 1H, Ar{2-CH}), 6.93 (dd, JHH = 8.2, JHH
=
2
3
2
2.5, 2H, Ar), 1.94–2.04 (m, 2H, PCH2), 1.67–1.76 (m, 4H, CH2), 2, 2H, Ar), 1.85 (dtd, JHH = 14.2, JHH = 7.4, JPH = 3.1, 1H,
1.50–1.61 (m, 2H, CH2), 1.36–1.44 (m, 4H, CH2), 1.22–1.34 (m, PCH2), 1.58–1.68 (m, 4H, CH2), 1.41–1.52 (m, 2H, CH2),
3
16H, CH2), 1.26 (d, JPH = 13.8, 18H, tBu), 0.58 (partially col- 1.16–1.40 (m, 20H, CH2), 1.01 (d, 3JPH = 12.0, 18H, tBu).
2
lapsed quartet, fwhm = 300 Hz, 6H, BH3).
13C{1H} NMR (126 MHz, toluene-d8): δ 160.8 (d, JPC = 9, Ar
2
3
3
13C{1H} NMR (151 MHz, CDCl3): δ 154.2 (d, JPC = 6, Ar{C}), {C}), 129.9 (s, Ar), 111.7 (d, JPC = 13, Ar), 109.4 (t, JPC = 11, Ar
129.6 (s, Ar), 116.9 (d, 3JPC = 3, Ar), 114.1 (t, 3JPC = 3, Ar{2-CH}), {2-CH}), 32.5 (d, 1JPC = 16, tBu{C}), 30.9 (d, 2JPC = 11, CH2), 29.1
1
2
1
32.8 (d, JPC = 37, tBu{C}), 30.7 (d, JPC = 12, CH2), 28.1 (s, (d, JPC = 24, PCH2), 28.9 (s, CH2), 28.5 (s, CH2), 28.2 (s, CH2),
1
3
3
CH2), 28.0 (s, CH2), 27.6 (s, CH2), 27.5 (s, CH2), 25.1 (d, JPC
=
28.1 (s, CH2), 25.4 (d, JPC = 15, CH2), 25.3 (d, JPC = 15, tBu
{CH3}).
33, PCH2), 24.8 (d, 3JPC = 3, tBu{CH3}), 22.3 (s, CH2).
31P{1H} NMR (243 MHz, CDCl3): δ 143.8 (partially collapsed
31P{1H} NMR (162 MHz, C6D6): δ 140.5 (s).
Preparation of POCOP-14′·O2. Following an adapted litera-
quartet, fwhm = 165 Hz).
HR ESI-MS (positive ion, 4 kV): 531.3840, [M + Na]+ (calcd ture procedure.27 To a stirred solution of POCOP-14′ (25.1 mg,
531.3844) m/z.28
Anal. Calcd for C28H56B2O2P2 (508.32 g mol−1): C, 66.16; H, (30% w/w in H2O, 16 µL, 0.16 mmol). The mixture was allowed
11.10; found: C, 66.09; H, 11.26.28
to warm to RT overnight before the volatiles were removed in
cis-12 (Rf = 0.42). Yield: 984 mg (45%, white crystalline vacuo. Toluene (1 mL) was added and the solution was stirred
solid). over 3 Å molecular sieves (45.2 mg) overnight. The solution
1H NMR (500 MHz, CDCl3): δ 7.20 (t, JHH = 8.3, 1H, Ar), was filtered, extracting the sieves with additional toluene (3 ×
52.2 µmol) in EtOH (2 mL) cooled to −78 °C was added H2O2
3
3
4
4
7.03 (dd, JHH = 8.3, JHH = 2.3, 2H, Ar), 6.82 (t, JHH = 2.5, 1H, 1 mL), and reduced to dryness to afford POCOP-14′·O2 as a col-
Ar{2-CH}), 1.90–2.06 (m, 2H, PCH2), 1.67–1.81 (m, 4H, CH2), ourless oil, which crystallised upon standing. Yield: 26.2 mg
3
1.53–1.66 (m, 2H, CH2), 1.20–1.50 (m, 20H, CH2), 1.26 (d, JPH (95%).
= 14.0, 18H, tBu), 0.61 (partially collapsed quartet, fwhm = 285
3
1H NMR (500 MHz, CD2Cl2): δ 7.23 (t, JHH = 8.3, 1H, Ar),
4
3
4
Hz, 6H, BH3).
7.19 (t, JHH = 2.4, 1H, Ar{2-CH}), 7.04 (dd, JHH = 8.3, JHH =
2
13C{1H} NMR (126 MHz, CDCl3): δ 154.4 (d, JPC = 6, Ar{C}), 7.1, 2H, Ar), 1.75–1.91 (m, 4H, CH2), 1.16–1.73 (m, 24H, CH2),
129.7 (s, Ar), 116.6 (d, 3JPC = 3, Ar), 113.4 (t, 3JPC = 4, Ar{2-CH}), 1.22 (d, 3JPH = 15.5, 18H, tBu).
1
2
2
32.9 (d, JPC = 37, tBu{C}), 30.5 (d, JPC = 12, CH2), 28.2 (s,
13C{1H} NMR (126 MHz, CD2Cl2): δ 153.6 (d, JPC = 10,
Ar{C}), 130.2 (s, Ar), 116.4 (d, JPC = 4, Ar), 113.3 (t, JPC = 4,
1
3
3
CH2), 27.9 (s, CH2), 27.8 (s, CH2), 27.6 (s, CH2), 25.2 (d, JPC
33, PCH2), 24.9 (d, 3JPC = 3, tBu{CH3}), 22.0 (d, 3JPC = 2, CH2).
=
1
2
Ar{2-CH}), 33.9 (d, JPC = 91, tBu{C}), 30.9 (d, JPC = 14, CH2),
This journal is © The Royal Society of Chemistry 2020
Dalton Trans.