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doi.org/10.1002/chem.202005433
Chemistry—A European Journal
J=0.9 Hz, 1H). 13C NMR (126 MHz, DMSO): d=175.9, 156.6, 156.5,
General procedure with additive (GP2)
155.2, 154.2, 153.1, 137.6, 136.8, 129.4, 127.4, 126.2, 126.0, 125.9,
125.8, 125.1, 124.8, 124.3, 123.7, 123.6, 122.9, 121.3, 121.2, 121.1,
121.0, 120.3, 115.5, 113.0, 112.0, 110.9, 110.3, 102.3, 63.7. HRMS
calcd for [C32H18N2O2+]: 462.1368, found: 462.1382.
Catalysis was performed as GP 1 with 1–5 equiv MsOH as additive.
After the reaction vial was cooled down to r.t. in water bath, and
the reaction mixture was filtered through basic alumina and Celite
and washed with DCM. Solvents were evaporated and the crude
products were purified by a flash column chromatography using
SiO2 as a stationary phase and mixtures of EtOAc:n-Hex as eluent.
Synthesis of 4c: Compound 4c was prepared following the GP2 at
708C with 1c (63.5 mg, 0.25 mmol), oAC-air(D) (113.5 mg) and
MsOH (33.1 mL, 0.51 mmol) with 16 h reaction time. Product was
purified using flash column chromatography with silica as station-
ary phase and EtOAc:n-Hex (1:4) as eluent. Yield was 25.8 mg,
Synthesis and characterisation
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41%. H NMR (500 MHz, [D6]DMSO): d=12.45 (s, 1H), 8.40 (d, J=
Synthesis of 3a: Compound 3a was prepared following the GP2
with 1a (29.5 mg, 0.13 mmol), oAC-air(D) (140.1 mg) and MsOH
(40.6 mL, 0.62 mmol) with 1.3 h reaction time. Product was purified
using flash column chromatography with silica as stationary phase
8.0 Hz, 1H), 8.36 (d, J=7.4 Hz, 1H), 8.17 (d, J=8.2 Hz, 1H), 8.14 (d,
J=8.1 Hz, 1H), 7.83 (d, J=7.7 Hz, 1H), 7.64 (d, J=7.6 Hz, 1H),
7.59–7.52 (m, 4H), 7.49–7.44 (m, 2H), 7.28 (dd, J=8.1, 7.0 Hz, 1H),
7.21 (dd, J=8.1, 7.0 Hz, 1H), 7.19–7.12 (m, 2H), 6.67 (d, J=0.7 Hz,
1H). 13C NMR (75 MHz, [D6]DMSO): d=178.8, 155.9, 146.5, 139.5,
138.7, 138.5, 138.3, 137.8, 137.5, 135.6, 129.8, 129.4, 126.7, 126.1,
126.1, 125.7, 125.6, 124.3, 124.3, 124.1, 123.4 (3C), 123.3, 122.1,
121.7, 121.1, 120.0 (2C), 114.9, 112.6, 64.6. 1H NMR (500 MHz,
[D6]acetone): d=11.36 (s, 1H), 8.52 (d, J=7.9 Hz, 1H), 8.41 (d, J=
7.7 Hz, 1H), 8.26 (d, J=8.1 Hz, 1H), 8.02 (d, J=8.1 Hz, 1H), 7.85–
7.80 (m, 1H), 7.61 (d, J=7.6 Hz, 1H), 7.55 (dtd, J=12.0, 7.9, 1.1 Hz,
3H), 7.51–7.42 (m, 3H), 7.28 (dd, J=8.2, 7.0 Hz, 1H), 7.23 (dd, J=
8.2, 7.0 Hz, 1H), 7.18–7.12 (m, 2H), 6.74 (d, J=0.8 Hz, 1H). 13C NMR
(126 MHz, [D6]acetone): d=180.1, 157.6, 148.0, 141.1, 140.2, 140.1,
139.8, 138.8, 138.6, 137.2, 131.2, 130.1, 127.4, 127.3, 127.1, 126.8,
126.4, 126.0, 125.0, 125.0, 124.8, 124.4, 124.1, 123.7, 122.8, 122.7,
122.1, 121.4, 121.3, 116.9, 113.4, 66.2. HRMS calcd for [C32H18S2N2+]:
494.0911; found: 494.0893 (Figure 7).
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and EtOAc:n-Hex (1:4) as eluent. Yield was 16.6 mg, 58%. H NMR
(500 MHz, [D6]DMSO): d=11.95 (s, 2H), 7.75 (d, J=8.9 Hz, 2H),
7.49–7.42 (m, 6H), 7.38–7.32 (m, 2H), 7.33 (d, J=8.2 Hz, 2H), 7.23
(dd, J=8.2, 7.0 Hz, 2H), 7.07 (dd, J=8.1, 7.0 Hz, 2H). 13C NMR
(75 MHz, DMSO): d=155.5, 146.9, 138.3, 127.0, 126.4, 125.6, 124.4,
123.6, 123.2, 121.0, 120.8, 119.6, 112.3, 112.1, 111.8, 111.8. HRMS cal-
culated for [C32H18N2O2+]: 462.1368, found: 494.1377.
Synthesis of 3c: Compound 3c was prepared following the GP2
with 1c (62.7 mg, 0.25 mmol), oAC-air(D) (281.5 mg) and MsOH
(32.6 mL, 0.50 mmol) with 6 h reaction time. Product was purified
using flash column chromatography with silica as fixed phase and
EtOAc:n-Hex (1:4) as eluent. Yield was 1.4 mg, 2%. 1H NMR
(500 MHz, [D6]DMSO): d=11.81 (s, 2H), 8.11 (d, J=8.1 Hz, 2H), 7.44
(m, 4H), 7.38 (d, J=8.0, 2H), 7.33 (dd, J=8.2, 7.2, 2H), 7.20 (dd, J=
8.2, 7.0, 2H), 7.1 (d, J=8.1, 2H), 7.05 (dd, J=8.0, 7.0, 2H). 13C NMR
(75 MHz, [D6]DMSO): d=140.0, 138.0, 137.7, 134.3, 130.2, 128.4,
126.8, 125.1, 124.7, 124.4, 123.0, 122.8, 120.5, 119.6, 111.9, 110.9.
HRMS calcd for [C32H18S2O2+]: 494.0911, found: 494.0899.
Synthesis of 3d: Compound 3d was prepared following the GP2
at 708C with 1d (44.5 mg, 0.19 mmol), oAC-HNO3 (226.0 mg) and
MsOH (61.7 mL, 0.95 mmol) with 17 h reaction time. Product was
purified using flash column chromatography with silica as station-
ary phase and EtOAc:n-Hex (1:40) as eluent. Yield was 9.8 mg,
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22%. H NMR (500 MHz, CDCl3): d=7.63 (d, J=8.4 Hz, 2H), 7.56 (d,
J=7.9 Hz, 2H), 7.43 (dd, J=8.5, 7.2 Hz, 2H), 7.31 (t, J=7.3 Hz, 2H).
13C NMR (126 MHz, CDCl3): d=157.0, 143.4, 127.3, 126.4, 123.6,
122.1, 115.6, 112.2. HRMS calcd for [C32H16O4+]: 464.1049, found:
464.1068.
Synthesis of 3e: Compound 3e was prepared following the GP2
with 1e (63.6 mg, 0.25 mmol), oAC-HNO3 (286.0 mg) and MsOH
(82.5 mL, 1.3 mmol) with 24 h reaction time. Product was purified
using flash column chromatography with silica as stationary phase
Figure 7. Molecular structure of one of the two crystallographic independ-
ent molecules of 4c (see Supporting Information).
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and EtOAc:n-Hex (1:40) as eluent. Yield was 22.4 mg, 35%. H NMR
Acknowledgements
(500 MHz, CD2Cl2): d=7.94 (d, J=8.2 Hz, 2H), 7.61 (d, J=8.2 Hz,
2H), 7.59 (d, J=7.7 Hz, 2H), 7.46–7.37 (m, 4H), 7.33–7.21 (m, 6H).
13C NMR (126 MHz, CD2Cl2): d=156.8, 148.0, 142.2, 138.9, 133.0,
131.9, 128.2, 126.3, 126.2, 125.4, 125.0, 123.9, 123.1, 122.1, 114.6,
112.3. HRMS calcd for [C32H16S2O2+]: 496.0592, found: 496.0578.
Financial support from Academy of Finland [project no. 129062
(J.H.)] is acknowledged. The Finnish National Centre for Scien-
tific Computing (CSC) is recognized for computational resour-
ces. D.S.C. is grateful to Magnus Ehrnrooth and Toso-Montanari
Foundations for funding, and M.Sc. Mikko Mäkelä for introduc-
tion into carbocatalysis and techniques to prepare our cata-
lysts. We also thank Dr. Sami Heikkinen for assistance in NMR
analysis.
Synthesis of 4a: Compound 4a was prepared following the GP2
with 1a (11.9 mg, 51.0 mmol), oAC-air(D) (33.1 mg) and MsOH
(9.7 mL, 0.15 mmol) with 5 h reaction time. Product was purified
using flash column chromatography with silica as stationary phase
and EtOAc:n-Hex (1:4 ! 1:9) as eluent. Yield was 9.3 mg, 79%.
1H NMR (500 MHz, [D6]DMSO): d=12.67 (s, 1H), 8.41–8.36 (m, 1H),
8.26 (d, J=8.2 Hz, 1H), 8.05–7.99 (m, 1H), 7.82–7.75 (m, 2H), 7.57–
7.50 (m, 2H), 7.50–7.45 (m, 2H), 7.41 (td, J=7.5, 1.1 Hz, 1H), 7.37
(dd, J=7.7, 1.3 Hz, 1H), 7.33–7.28 (m, 2H), 7.28–7.23 (m, 1H), 7.11
(ddd, J=8.4, 7.2, 1.5 Hz, 1H), 7.06 (td, J=7.4, 1.1 Hz, 1H), 6.12 (d,
Chem. Eur. J. 2021, 27, 5283 –5291
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