E
B. Liu, B.-F. Shi
Letter
Synlett
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(15) General Procedure for the Lactonization
To a 50 mL Schlenk tube was added substrate (0.2 mmol),
Pd(OAc)2 (4.5 mg, 0.02 mmol), PhI(OAc)2 (128.8 mg, 0.4 mmol),
NaI (30 mg, 0.1 mmol), AgOAc (16.7 mg, 0.1 mmol), and toluene
(2 mL). This tube was charged with N2, and the mixture was
then heated at 100 °C for 24 h. The reaction mixture was cooled
to room temperature, diluted with EtOAc, and quenched with
water. The aqueous phase was extracted with EtOAc (3 × 10
mL). The combined organic phase was dried with anhydrous
MgSO4. After concentration, purification by flash chromatogra-
phy gave target products.
(8) For the development and application of PIP directing group in
methylene C(sp3)–H functionalization, see: (a) Chen, F.-J.; Zhao,
S.; Hu, F.; Chen, K.; Zhang, Q.; Zhang, S.-Q.; Shi, B.-F. Chem. Sci.
2013, 4, 4187. (b) Zhang, Q.; Chen, K.; Rao, W.-H.; Zhang, Y.-J.;
Chen, F.-J.; Shi, B.-F. Angew. Chem. Int. Ed. 2013, 52, 13588.
(c) Zhang, Q.; Yin, X.-S.; Zhao, S.; Fang, S.-L.; Shi, B.-F. Chem.
Commun. 2014, 50, 8353. (d) Chen, F.-J.; Liao, G.; Li, X.; Wu, J.;
Shi, B.-F. Org. Lett. 2014, 16, 5644. (e) Yan, S.-Y.; Liu, Y.-J.; Liu, B.;
Liu, Y.-H.; Shi, B.-F. Chem. Commun. 2015, 51, 4069. For an appli-
cation of the PIP directing group in total synthesis: (f) Dailler,
D.; Danoun, G.; Baudoin, O. Angew. Chem. Int. Ed. 2015, 54, 4919.
(9) (a) Giri, R.; Maugel, N.; Li, J.-J.; Wang, D.-H.; Breazzano, S. P.;
Saunders, L. B.; Yu, J.-Q. J. Am. Chem. Soc. 2007, 129, 3510.
(b) Mei, T.-S.; Giri, R.; Maugel, N.; Yu, J.-Q. Angew. Chem. Int. Ed.
2008, 47, 5215.
(16) 2-(5-Oxotetrahydrofuran-2-yl)-N-[2-(pyridin-2-yl)propan-2-
yl]acetamide (2a)
The title compound 2a was prepared according to general pro-
cedure for the lactonization. Purification by flash chromatogra-
phy in EtOAc gave the desired product as a white solid in 75%
yield. 1H NMR (400 MHz, CDCl3): δ = 8.50 (d, J = 4.4 Hz, 1 H),
7.95 (s, 1 H), 7.72 (td, J = 7.8, 1.8 Hz, 1 H), 7.39 (d, J = 8.1 Hz, 1 H),
7.20 (ddd, J = 7.4, 4.9, 0.9 Hz, 1 H), 4.95 (m, 1 H), 2.75 (dd, J =
14.7, 6.5 Hz, 1 H), 2.63–2.52 (m, 3 H), 2.51–2.40 (m, 1 H), 2.12–
1.99 (m, 1 H), 1.75 (s, 3 H), 1.74 (s, 3 H). 13C NMR (100 MHz,
CDCl3): δ = 176.99, 167.87, 164.32, 147.84, 137.45, 122.23,
119.66, 57.02, 43.34, 29.94, 28.93, 27.92, 27.69, 27.66. HRMS
(EI-TOF): m/z calcd for C14H18N2O3 [M+]: 262.1317; found:
262.1311.
(10) For selected reviews, see: (a) Ma, J.-A.; Cahard, J. J. Fluorine
Chem. 2007, 128, 975. (b) Furuya, T.; Kamlet, A. S.; Ritter, T.
Nature (London, U.K.) 2011, 473, 470. (c) Tomashenko, O. A.;
Grushin, V. V. Chem. Rev. 2011, 111, 4475. (d) Zhou, Y.; Wang, J.;
© Georg Thieme Verlag Stuttgart · New York — Synlett 2016, 27, A–E