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X. Li et al.
Letter
Synlett
tion through an outer-sphere process. The external acetate,
rather than the palladium-coordinated acetate, attacks
from the less-hindered face of the terminal olefin; subse-
quent reductive elimination then gives the allylic oxidation
product. Finally, benzoquinone (BQ) oxidizes Pd(0) to re-
generate the active catalyst species Pd(II).11
Supporting Information
Supporting information for this article is available online at
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References and Notes
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(4) (a) Chen, M. S.; Prabagaran, N.; Labenz, N. A.; White, M. C. J. Am.
Chem. Soc. 2005, 127, 6970. (b) Reed, S. A.; White, M. C. J. Am.
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11176. (g) Howell, J. M.; Liu, W.; Young, A. J.; White, M. C. J. Am.
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Calleja, P.; Vermeulen, N. A.; Mizuno, T.; White, M. C. J. Am.
Chem. Soc. 2016, 138, 1265.
R2
AcO
DHQ
R1
Pd
L
AcOH
OAc
M1
R2
R1
O
H
O
O
O
Pd
L
Pd
L
M2
M6
R1
Rate-determining
step
AcO
R2
BQ
R2
R1
R1
HO
O
AcO
R2
R1
AcO-
L
Pd
R2
Pd
M5
L
M3
Selectivity-determining step
Pd
L
(5) (a) Henderson, H.; Check, C. T.; Proust, N.; Stambuli, J. P. Org.
Lett. 2010, 12, 824. (b) Le, C.; Kunchithapatham, K.; Henderson,
W. H.; Check, C. T.; Stambuli, J. P. Chem. Eur. J. 2013, 19, 11153.
(6) Uemura, S.; Fukuzawa, S.; Toshimitsu, A.; Okano, M. Tetrahedron
Lett. 1982, 23, 87.
(7) (a) Senthil, K.; Akiba, U.; Fujiwara, K.; Hamada, F.; Kondo, Y. Ind.
Eng. Chem. Res. 2017, 56, 1036. (b) Zheng, Y.; Du, M.; Li, J.-R.;
Zhang, R.-H.; Bu, X.-H. Dalton Trans. 2003, 1509. (c) Deckert, C.;
Bittner, D.; Carrella, L. M.; Schollmeyer, D.; Rentschler, E. Eur. J.
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M4
Scheme 3 Proposed mechanism cycle
In summary, we have developed a novel palladium(II)–
thiadiazole ligand system that catalyzes the oxidation of
1,1-disubstituted olefins to give a variety of allylic acetates.
The use of the cheap and easily prepared monothiadiazole
ligand makes this transformation environmentally friendly
and practical. A variety of 1,1-disubstituted olefins, mono-
terpenes, and cyclic olefins are tolerated in this procedure,
which proceeds smoothly to give the corresponding prod-
ucts in moderate to excellent yields. Further studies on the
carbon–nitrogen cross-coupling of sulfonamides with ole-
fins are in progress.
(9) Allylic Acetates 2a–r; General Procedure
To a stirred mixture of Pd(OAc)2 (0.05 equiv), ligand L6 (0.05
equiv), Et3N (2.0 equiv), and 1,4-benzoquinone (2.0 equiv) in
AcOH (1 mL) was added the appropriate substrate (1.00 mmol)
in one portion at r.t. The resultant mixture was stirred at 40 °C
for 12–24 h then cooled to r.t. The reaction was quenched with
sat. aq NaHSO3, and the mixture was diluted with H2O and
CH2Cl2. The organic layer was separated, and the aqueous layer
was extracted with CH2Cl2. The combined organic layers were
dried (Na2SO4), filtered, and concentrated under reduced pres-
sure to afford a brown oil that was purified by column chroma-
tography (silica gel, CH2Cl2–hexane or EtOAc–hexane) to afford
the allylic acetate as a colorless to pale-yellow oil or solid.
2-[(2R,8R,8aS)-8,8a-Dimethyl-6-oxo-1,2,3,4,6,7,8,8a-octahy-
dronaphthalen-2-yl]prop-2-en-1-yl Acetate (2n)
Prepared according to the general procedure from (+)-nootka-
tone (218 mg, 1.00 mmol). The crude product was purified by
column chromatography [silica gel, EtOAc–hexane (1:10)] to
give a white solid; yield: 168 mg (61%, 0.61 mmol). 1H NMR
(500 MHz, CDCl3): = 5.75 (s, 1 H), 5.07 (s, 1 H), 4.97 (s, 1 H),
4.60–4.54 (m, 2 H), 2.50 (m, 1 H), 2.37 (m, 2 H), 2.28–2.18 (m, 2
Funding Information
This work was supported by the National Natural Science Foundation
of China (21676252).
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Acknowledgment
We are grateful to the Collaborative Innovation Center of Yangtze Riv-
er Delta Region Green Pharmaceuticals for financial help.
© Georg Thieme Verlag Stuttgart · New York — Synlett 2019, 30, A–E