E
S. Wang et al.
Letter
Synlett
(4) For selected reports on ring-opening 1,3-difunctionalizations
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Sodium dispersion (10.0 M, 0.40 mL, 4.0 mmol) was then added
dropwise, and the resulting suspension was stirred at –78 °C for
1.5 h. The resulting mixture was warmed to 0 °C, and the reac-
tion was then quenched with i-PrOH (0.31 mL, 4.0 mmol) and
then aqueous NH4Cl (5 mL). The resulting biphasic solution was
extracted with EtOAc (4 × 10 mL). The combined organic layer
was dried over Na2SO4, filtered, and concentrated under
reduced pressure. The residue was purified by column chroma-
tography (hexane to hexane/EtOAc = 30:1) on silica gel to
provide 2a as a white solid (81% yield, 359 mg, 0.801 mmol,
syn/anti = 89:11); mp 120–130 °C. 1H NMR (600 MHz, CDCl3):
= 7.21 (dd, J = 7.5, 7.5 Hz, 0.89 × 4 H + m, 0.11 × 4 H), 7.13 (d,
J = 7.5 Hz, 0.89 × 4 H + m, 0.11 × 4 H), 7.10 (t, J = 7.5 Hz, 0.89 × 2 H +
m, 0.11 × 2 H), 2.36 (ddd, J = 14.4, 7.8, 7.8 Hz, 0.89 × 1 H), 2.30 (t,
J = 7.8 Hz, 0.89 × 2 H), 2.25 (dd, J = 9.6, 6.6 Hz, 0.11 × 2 H), 2.21
(t, J = 6.6 Hz, 0.11 × 2 H), 2.02 (ddd, J = 14.4, 7.8, 7.8 Hz, 0.89 ×
1 H), 1.20 (s, 0.89 × 12 H), 1.18 (s, 0.89 × 12 H), 1.15 (s, 0.11 ×
12 H), 1.14 (s, 0.11 × 12 H). 13C NMR (151 MHz, CDCl3): (syn
isomer) = 143.3, 128.6, 128.4, 125.3, 83.3, 35.2, 31.3 (br), 24.8.
11B NMR (192 MHz, CDCl3): = 33.1 (br). HRMS (APCI-MS, posi-
tive): m/z = 448.2957. Anal. Calcd for C27H38B2O4: 448.2960 [M]+.
(10) The relative stereochemistry of 2a was unambiguously assigned
after oxidation to the corresponding diol with retention of the
stereochemistry.
(11) Organolithium compounds can react with electrophiles with
either retention or inversion of the stereochemistry of the
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Aggarwal, V. K. Angew. Chem. Int. Ed. 2016, 55, 14663. (b) Blair,
B. J.; Tanini, D.; Bateman, J. M.; Scott, H. K.; Myers, E. L.;
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(8) Sodium dispersion as a highly reactive yet easy-to-handle
reducing agent, see: (a) An, J.; Work, D. N.; Kenyon, C.; Procter,
D. J. J. Org. Chem. 2014, 79, 6743. (b) Han, M.; Ma, X.; Yao, S.;
Ding, Y.; Yan, Z.; Adijiang, A.; Wu, Y.; Li, H.; Zhang, Y.; Lei, P.;
Ling, Y.; An, J. J. Org. Chem. 2017, 82, 1285. (c) Li, H.; Zhang, B.;
Dong, Y.; Liu, T.; Zhang, Y.; Nie, H.; Yang, R.; Ma, X.; Ling, Y.; An,
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Li, H.; Luo, S.; Adijiang, A.; Ling, Y.; An, J. Org. Lett. 2018, 20,
3010. (e) Lei, P.; Ding, Y.; Zhang, X.; Adijiang, A.; Li, H.; Ling, Y.;
An, J. Org. Lett. 2018, 20, 3439. (f) Zhang, B.; Li, H.; Ding, Y.; Yan,
Y.; An, J. J. Org. Chem. 2018, 83, 6006. (g) Ding, Y.; Luo, S.;
Adijiang, A.; Zhao, H.; An, J. J. Org. Chem. 2018, 83, 12269.
(h) Asako, S.; Nakajima, H.; Takai, K. Nat. Catal. 2019, 2, 297.
(i) Asako, S.; Kodera, M.; Nakajima, H.; Takai, K. Adv. Synth. Catal.
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Chem. 2019, 84, 15827.
(13) B(OMe)3 was used as an electrophile instead of MeOBpin
because diol 7 was difficult to separate chromatographically on
silica gel from pinacol generated from hydrolysis of the Bpin
group.
(9) Experimental Procedure
An oven-dried 20 mL Schlenk tube was charged with 4,4′-di-
tert-butylbiphenyl (DTBB, 53.3 mg, 0.200 mmol), THF (4.0 mL),
and trans-1a (191 mg, 0.983 mmol). After the mixture was
cooled to –78 °C, MeOBpin (0.97 mL, 6.0 mmol) was added.
(14) Bonet, A.; Odachowski, M.; Leonori, D.; Essafi, S.; Aggarwal, V. K.
Nat. Chem. 2014, 6, 584.
(15) Although the anti-isomer of 8 is likely to be formed in less than
5% yield, we could not isolate the isomer.
© 2020. Thieme. All rights reserved. Synlett 2020, 52, A–E