Paper
Organic & Biomolecular Chemistry
the coupling partner (8.25 mmol) and the chosen base
(2.25 mmol) were emulsified in 15 mL of 2 wt% surfactant
Product 8. Eluent toluene/Et2O 99 : 1.
1H NMR (400 MHz, CDCl3): δ[ppm] 7.67 (d, J = 8.6 Hz, 2H),
aqueous solution by sonication in an ultrasound bath for 7.50 (d, J = 8.6 Hz, 2H), 6.78 (m, 1H), 6.35 (dd, J = 3.7, 1.7 Hz,
15 minutes. In the case of reactions performed using 1H), 6.23 (dd, J = 3.7, 2.7 Hz, 1H), 3.71 (s, 3H).27
PTh–OMe, the catalyst was dissolved in the organic phase and
emulsified as well. In the case of reactions performed using
Product 9. Eluent heptane/AcOEt 95 : 5.
1H NMR (400 MHz, CDCl3): δ[ppm] 6.61 (t, J = 2.2 Hz, 1H),
S-PTh, the catalyst (137 mg, 0.150 mmol) was dissolved in 6.21 (dd, J = 3.7, 1.7 Hz, 1H), 6.10 (t, J = 3.1 Hz, 1H), 4.71 (s,
water with the amount of K-EL (163 mg) necessary to obtain a 1H), 4.20–4.28 (m, 4H), 3.59 (s, 3H), 1.29 (t, 7.1 Hz, 6H).41
2 wt% aqueous solution of both surfactants. 12 mL of this
emulsion were subsequently recirculated within the reactor
Product 10. Eluent heptane/AcOEt 95 : 5.
1H NMR (400 MHz, CDCl3): δ[ppm] 8.15 (d, J = 8.4 Hz, 2H),
under irradiation for an appropriate amount of time. The 7.65 (d, J = 7.8 Hz, 1H), 7.60 (d, J = 8.4 Hz, 2H), 7.38 (d, J =
remaining 3 mL were used as a reservoir to replenish the 8.3 Hz, 1H), 7.28 (t, J = 7.5 Hz, 1H), 7.16 (t, J = 7.5 Hz, 1H), 6.65
reactor after sampling the reaction for GC-MS analysis. (s, 1H), 4.43 (q, J = 7.1 Hz, 2H), 3.78 (s, 3H), 1.43 (t, J = 7.1 Hz,
Samples for GC-MS analysis were prepared extracting 0.2 mL 3H).40
of the reaction mixture with 2 mL of DCM, and filtering the
organic phase on cotton wool to remove water and salt
residues.
Author contributions
Specifically, in the case of the reaction described in Table 2,
LB and SM contributed to the conceptualization and supervi-
entry 10 for the synthesis of product 1. 14 mL of the reaction
sion. FP, SM and PMCR contributed to the writing of the orig-
mixture were used out of the 15 mL prepared. At the end of the
inal draft. LB and MS contributed to review and editing. FP,
reaction, water was removed under reduced pressure, and the
SM and ES performed the investigation. PMCR provided
resources.
raw mixture was taken with DCM. The precipitate was filtered,
and the crude product was purified by column chromato-
graphy using heptane/AcOEt 8 : 2 as the eluent. Isolated
product: 209 mg, 65% yield.38
1H NMR (400 MHz, CDCl3): δ[ppm] 8.06 (d, J = 8.6 Hz, 2H),
7.47 (d, J = 8.6 Hz, 2H), 6.73 (m, 1H), 6.33 (dd, J = 3.7, 1.8 Hz,
1H), 6.22 (dd, J = 3.7, 2.6 Hz, 1H), 4.39 (q, J = 7.1 Hz, 2H), 3.71
(s, 3H), 1.41 (t, J = 7.1 Hz, 3H).
Conflicts of interest
There are no conflicts to declare.
Acknowledgements
General procedures for reactions performed with the Chemtrix
Labtrix® Start reactor
LB, MS, SM and FP gratefully acknowledge financial contri-
bution for MIUR under grants “Dipartimenti di Eccellenza
2017 Project – Materials for Energy” and PRIN2017 BOOSTER
(2017YXX8AZ).
The procedure applies for the reactions in Scheme 4. A stock
solution of S-PTh (273 mg, 0.300 mmol) and K-EL (327 mg) in
water (30 mL) was prepared and used to perform all the
described couplings. The halide (0.1000 mmol), the coupling
partner (0.5500 mmol) and the TEA (22.38 mg, 0.1500 mmol)
were emulsified in 1 mL of the S-PTh/K-EL aqueous stock solu-
tion by sonication in an ultrasound bath for 15 minutes. This
emulsion was subsequently injected within the reactor under
irradiation at a 0.1 μL min−1 flow rate, remaining under illumi-
nation for 100 minutes. Samples for GC-MS analysis were pre-
pared extracting 0.2 mL of the reaction mixture with 2 mL of
DCM and filtering the organic phase on cotton wool to remove
water and salt residues. An analytical sample for each
described product was obtained by chromatographic purifi-
cation of the residual extract.
Notes and references
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Product 4. Eluent heptane/DCM 1 : 1.
1H NMR (400 MHz, CDCl3): δ[ppm] 7.27 (dd, J = 5.1, 1.2 Hz,
1H), 7.07 (m, 1H), 7.03 (dd, J = 3.6, 1.1 Hz, 1H), 6.71 (m, 1H),
6.34 (d, J = 3.5 Hz, 1H), 6.18 (m, 1H), 3.73 (s, 3H).39
Product 7. Eluent heptane/DCM 1 : 1.
1H NMR (400 MHz, CDCl3): δ[ppm] 7.69 (d, J = 8.4 Hz, 2H),
7.55–7.60 (m, 3H), 7.32 (d, J = 8.3 Hz, 1H), 7.23 (t, J = 7.5 Hz,
1H), 7.10 (t, J = 7.5 Hz, 1H), 6.59 (s, 1H), 3.71 (s, 3H).40
3022 | Org. Biomol. Chem., 2021, 19, 3016–3023
This journal is © The Royal Society of Chemistry 2021