E
C. B. Cheong et al.
Letter
Synlett
(5) For a selected example whereby the acetate group is involved in
a Meyer–Schuster rearrangement, see: Engel, D. A.; Dudley, G. B.
Org. Biomol. Chem. 2009, 7, 4149.
(14) (a) Wessely, F.; Lauterbach-Keil, G.; Schmid, F. Monatsh. Chem.
1950, 81, 811. (b) Wessely, F.; Sinwel, F. Monatsh. Chem. 1950,
81, 1055. (c) Metlesics, W.; Wessely, F.; Budzikiewicz, H. Mona-
tsh. Chem. 1958, 89, 102. (d) Wessely, F.; Budzikiewicz, H. Mona-
tsh. Chem. 1959, 90, 62. (e) Adler, E.; Brasen, S.; Miyake, H. Acta.
Chem. Scand. 1971, 25, 2055. (f) Becker, H.-D.; Bremholt, T.;
Adler, E. Tetrahedron Lett. 1972, 13, 4205.
(6) (a) Frost, J. R.; Cheong, C. B.; Akhtar, W. M.; Caputo, D. F. J.;
Stevenson, N. G.; Donohoe, T. J. J. Am. Chem. Soc. 2015, 137,
15664. (b) Akhtar, W. M.; Cheong, C. B.; Frost, J. R.; Christensen,
K. E.; Stevenson, N. G.; Donohoe, T. J. J. Am. Chem. Soc. 2017, 139,
2577. (c) Akhtar, W. M.; Armstrong, R. J.; Frost, J. R.; Stevenson,
N. G.; Donohoe, T. J. J. Am. Chem. Soc. 2018, 140, 11916.
(d) Armstrong, R. J.; Akhtar, W. A.; Young, T. A.; Duarte, F.;
Donohoe, T. J. Angew. Chem. Int. Ed. 2019, 58, 12558.
(e) Armstrong, R. J.; Akhtar, W. M.; Frost, J. R.; Christensen, K. E.;
Stevenson, N. G.; Donohoe, T. J. Tetrahedron 2019, 75, 130680.
(f) Wübbolt, S.; Cheong, C. B.; Frost, J. R.; Christensen, K. E.;
Donohoe, T. J. Angew. Chem. Int. Ed. 2020, 59, 11339.
(7) Baeyer, A.; Villiger, V. Ber. Dtsch. Chem. Ges. 1899, 32, 3625.
(8) (a) For 1 (bromide), see: Mudyiwa, M.; Ndinguri, M. W.; Soper,
S. A.; Hammer, R. P. J. Porphyrins Phthalocyanines 2010, 14, 891.
For 2 (methyl ester), see: (b) Jiménez-Rodriguez, C.; Eastham, G.
R.; Cole-Hamilton, D. J. Inorg. Chem. Commun. 2005, 8, 878.
(9) Previous conditions for the cleavage of related (mesityl) func-
tional groups required the use of strong protic acids, see:
(a) Schubert, W. M.; Latourette, H. K. J. Am. Chem. Soc. 1952, 74,
1829. (b) Bender, M. L.; Ladenheim, H.; Chen, M. C. J. Am. Chem.
Soc. 1961, 83, 123. (c) Bender, M. L.; Chen, M. C. J. Am. Chem. Soc.
1963, 85, 37.
(15) Yuan, C.; Eliasen, A. M.; Camelio, A. M.; Siegel, D. Nat. Protoc.
2014, 9, 2624.
(16) Ph*OH could also be cleaved using IBr, providing a mixture of
phenolic esters as the major product(s). TFA (aq.) was also effec-
tive but is quite harsh, whilst methanolic HCl did not cleave
Ph*OH at RT (see SI for these examples). These conditions were
not investigated further.
(17) Yoshimura, A.; Zhdankin, V. V. Chem. Rev. 2016, 116, 3328.
(18) Typical Procedure for CAN-Mediated Cleavage: Synthesis of 16
To a solution of phenol 14 (28.2 mg, 0.10 mmol) in MeOH (1.0
mL) was titrated a solution of CAN (272 mg, 0.50 mmol) in
MeOH (0.5 mL) at RT in the open atmosphere until the color of
the CAN solution persisted (orange, typically 4–5 equiv). The
reaction mixture was diluted with H2O (3 mL) and stirred for 5–
10 min, then further diluted with CH2Cl2 (2 mL), and saturated
with NaCl. The layers were separated, the aqueous layer
extracted with CH2Cl2 (5 × 1.5 mL), the combined organics dried
(Na2SO4) and concentrated in vacuo. Purification by flash
column chromatography (SiO2, eluent: pentane–Et2O, 99:1)
afforded ester 16 (10.1 mg, 61%) as a volatile colorless oil. IR
(film): max = 3087, 3064, 3028, 3002, 2952, 1735, 1604, 1497,
1454, 1436, 1365, 1293, 1255, 1195, 1161, 1079, 1029, 986,
(10) El-Khawaga, A.; Roberts, R.; Sweeney, K. M. J. Org. Chem. 1985,
50, 2055.
(11) For selected recent reviews on gold catalysis in synthesis, see:
(a) Pflästerer, D.; Hashmi, A. S. K. Chem. Soc. Rev. 2016, 45, 1331.
(b) Zi, W.; Toste, F. D. Chem. Soc. Rev. 2016, 45, 4567.
(c) Shahzad, S. A.; Sajid, M. A.; Khan, Z. A.; Canseco-Gonzalez, D.
Synth. Commun. 2017, 47, 735.
(12) For selected reviews on HFIP, see: (a) Bégué, J.; Bonnet-Delpon,
D.; Crousse, B. Synlett 2004, 18. (b) Colomer, I.; Chamberlain, A.
E. R.; Haughey, M. B.; Donohoe, T. J. Nat. Rev. Chem. 2017, 1, 88.
(13) A control experiment using TMSCl (2.0 equiv) in CH2Cl2 at RT
was performed and gave only unreacted starting material.
950, 896, 837, 771, 750, 699 cm–1 1H NMR (500 MHz, CDCl3):
.
= 7.38–7.26 (2 H, m, Ph), 7.25–7.17 (3 H, m, Ph), 3.68 (3 H, s,
OCH3), 3.05–2.90 (2 H, m, CH2Ph), 2.68–2.58 (2 H, m,
CH2COOCH3). 13C NMR (126 MHz, CDCl3): = 173.5 (C=O), 140.6
(ArC), 128.6 (2 C, 2 × ArCH), 128.4 (2 C, 2 × ArCH), 126.4 (ArCH),
51.8 (OCH3), 35.8 (CH2COOCH3), 31.1 (CH2Ph).
(19) Womack, G.; Angeles, J. G.; Fanelli, V. E.; Heyer, C. A. J. Org.
Chem. 2007, 72, 7046.
© 2020. Thieme. All rights reserved. Synlett 2020, 31, A–E