DOI: 10.1039/C7CC08897C
ChemComm
ARTICLE
Journal Name
Reddy, B. V. S. Reddy, E. J. Corey, Org. Lett., 2006, 8, 2819; (c) R.
Fan, D. Pu, F. Wen, J. Wu, J. Org. Chem., 2007, 72, 8994; (d) T. Liu,
T.-S. Mei, J.-Q. Yu, J. Am. Chem. Soc., 2015, 137, 5871; (e) B. J.
Groendyke, D. I. AbuSalim, S. P. Cook, J. Am. Chem. Soc., 2016, 138,
12771.
9 For selected examples of visible light-promoted HLF reaction: (a) C.
Martínez, K. Muñiz, Angew. Chem. Int. Ed., 2015, 54, 8287; (b) Q. Qin,
S. Yu, Org. Lett., 2015, 17, 1894; (c) E. A. Wappes, S. C. Fosu, T. C.
Chopko, D. A. Nagib, Angew. Chem. Int. Ed., 2016, 55, 9974; (d) W.
Shu, C. Nevado, Angew. Chem. Int. Ed., 2017, 56, 1881; (e) G. J. Choi,
Q. Zhu, D. C. Miller, C. J. Gu, R. R. Knowles, Nature, 2016, 539, 268;
(f) J. C. K. Chu, T. Rovis, Nature, 2016, 539, 272.
In summary, we have developed a new method for radical-
mediated β-selective C(sp3)-H amidation of O-alkyl trichloro- or
arylimidates using NIS. This method offers a convenient and
generally applicable means for C(sp3)-H functionalization of
alcohols. This amidation reaction exhibits broad substrate scope,
and proceeds with high efficiency with primary, secondary and
tertiary β C(sp3)-H bonds. This method provides a useful
synthetic approach to various oxazolines and 2-amino alcohols
starting from easily accessible alcohols. Mechanistic studies
suggest that a HLF-type pathway through cyclization of a Cβ-
iodinated intermediate might be operative for certain substrates.
However, cyclization through a β carbocation intermediate
cannot be ruled out.
10 (a) K. Chen, J. M. Richter, P. S. Baran, J. Am. Chem. Soc., 2008, 130,
7247; (b) K. Chen, P. S. Baran, Nature, 2009, 459, 824.
11 For selected reviews on C-H amination: (a) F. Collet, C. Lescot, P.
Dauban, Chem. Soc. Rev., 2011, 40, 1926; (b) J. L. Jeffrey, R. Sarpong,
Chem. Sci., 2013, 4, 4092; (c) W. A. Nack, G. Chen, Synlett, 2015, 26,
2505; (d) J. Jiao, K. Murakami, K. Itami, ACS Catal., 2016, 6, 610; (e)
Y. Park, Y. Kim, S. Chang, Chem. Rev., 2017, 117, 9247.
Acknowledgements
12 For selected examples of C(sp3)-H aminaton of alcohols: (a) R. E.
Banks, N. J. Lawrence, M. K. Besheesh, A. L. Popplewell, R. G.
Pritchard, Chem. Commun., 1996, 1629; (b) Q. Michaudel, D. Thevenet,
P. S. Baran, J. Am. Chem. Soc., 2012, 134, 2547.
We greatly thank Natural Science Foundation of China
(21421062, 21502098, 21672105) for financial support.
Notes and references
13 For recent reviews on reactions involving nitrogen centered radicals:
(a) S. M. Zard, Chem. Soc. Rev., 2008, 37, 1603; (b) S. Chiba, H. Chen,
Org. Biomol. Chem., 2014, 12, 4051; (c) J.-R. Chen, X.-Q. Hu, L.-Q.
Lu, W.-J. Xiao, Chem. Soc. Rev., 2016, 45, 2044.
14 For selected examples of C-H functionalization involving nitrogen
radicals: (a) Y.-F. Wang, H. Chen, X. Zhu, S. Chiba, J. Am. Chem. Soc.,
2012, 134, 11980; (b) H. Chen, S. Sanjaya, Y.-F. Wang, S. Chiba, Org.
Lett., 2013, 15, 212; (c) J. Huang, Y. He, Y. Wang, Q. Zhu, Chem. Eur.
J., 2012, 18, 13964; (d) K. Kiyokawa, T. Kosaka, T. Kojima, S.
Minakata, Angew. Chem. Int. Ed., 2015, 54, 13719; (e) H.-B. Zhao, Z.-
W. Hou, Z.-J. Liu, Z.-F. Zhou, J. Song, H.-C. Xu, Angew. Chem. Int.
Ed., 2017, 56, 587.
State Key Laboratory and Institute of Elemento-Organic Chemistry,
College of Chemistry, Nankai University, Tianjin 300071, China
Electronic Supplementary Information (ESI) available: [details of any
supplementary information available should be included here]. See
DOI: 10.1039/b000000x/
1
For selected reviews on metal-catalyzed C(sp3)–H functionalization: (a) 15 For selected reviews on the synthesis and applications of oxazolines:
R. Jazzar, J. Hitce, A. Renaudat, J. Sofack-Kreutzer, O. Baudoin, Chem.
Eur. J., 2010, 16, 2654; (b) T. W. Lyons, M. S. Sanford, Chem. Rev.,
2010, 110, 1147; (c) H. Li, B.-J. Li, Z.-J. Shi, Catal. Sci. Technol., 2011,
(a) J. A. Frump, Chem. Rev., 1971, 71, 483; (b) J. S. Johnson, D. A.
Evans, Acc. Chem. Res., 2000, 33, 325; (c) S. Liao, X.-Li. Sun, Y. Tang,
Acc. Chem. Res., 2014, 47, 2260.
1, 191; (d) J. L. Roizen, M. E. Harvey, J. Du Bois, Acc. Chem. Res., 16 During the preparation of this manuscript, Nagib reported radical-
mediated C(sp3)-H amidation of imidates under visible light-promoted
conditions. E. A. Wappes, K. M. Nakafuku, D. A. Nagib, J. Am. Chem.
Soc., 2017, 139, 10204.
2012, 45, 911; (e) J. He, M. Wasa, K. S. L. Chan, Q. Shao, J.-Q. Yu,
Chem. Rev., 2017, 117, 8754.
2 A recent review on metal-catalyzed C–H functionalization of alcohols:
F. Mo, J. R. Tabor, G. Dong, Chem. Lett., 2014, 43, 264.
17 For selected reviews on synthesis and application of 1,2-amino
alcohols: (a) D. J. Ager, I. Prakash, D. R. Schaad, Chem. Rev., 1996, 96,
835; (b) S. C. Bergmeier, Tetrahedron, 2000, 56, 2561; (c) T. J.
Donohoe, C. K. A. Callens, A. Flores, A. R. Lacy, A. H. Rathi, Chem.
Eur. J., 2011, 17, 58.
3 For selected examples of C(sp3)-H amination of alcohols via metal
catalyzed nitrene insertion: (a) C. G. Espino, J. Du Bois, Angew. Chem.
Int. Ed., 2001, 40, 598; (b) C. G. Espino, P. M. Wehn, J. Chow, J. Du
Bois, J. Am. Chem. Soc., 2001, 123, 6935; (c) J.-L. Liang, S.-X. Yuan,
J.-S. Huang, W.-Y. Yu, C.-M. Che, Angew. Chem. Int. Ed., 2002, 41,
3465; (d) D. E. Olson, J. Du Bois, J. Am. Chem. Soc., 2008, 130, 11248.
4 For selected examples of metal-catalyzed C(sp3)-H functionalization of
alcohols: (a) K. J. Fraunhoffer, M. C. White, J. Am. Chem. Soc., 2007,
129, 7274; (b) E. M. Simmons, J. F. Hartwig, Nature, 2012, 483, 70; (c)
Z. Ren, F. Mo, G. Dong, J. Am. Chem. Soc., 2012, 134, 16991; (d) Y.
Xu, G. Yan, Z. Ren, G. Dong, Nat. Chem., 2015, 7, 829; (e) T. Kang,
H. Kim, J. G. Kim, S. Chang, Chem. Commun., 2014, 50, 12073; (f) X.
Huang, Y. Wang, J. Lan, J. You, Angew. Chem. Int. Ed., 2015, 54, 9404;
(g) Y. Dong, G. Liu, J. Org. Chem., 2017, 82, 3864.
18 For selected examples of imidate directed C(sp2)-H functionalization:
(a) D.-G. Yu, M. Suri, F. Glorius, J. Am. Chem. Soc., 2013, 135, 8802;
(b) X. Wang, A. Lerchen, F. Glorius, Org. Lett., 2016, 18, 2090; (c) X.
Wang, N. Jiao, Org. Lett., 2016, 18, 2150; (d) F. Wang, H, Wang, Q.
Wang, S. Yu, X. Li, Org. Lett., 2016, 18, 1306.
19 (a) C. K. McClure, A. J. Kiessling, J. S. Link, Tetrahedron, 1998, 54,
7121; (b) R. Viswanathan; E. N. Prabhakaran, M. A. Plotkin, J. N.
Johnston, J. Am. Chem. Soc., 2003, 125, 163; for a recent review see:
(c) D. Liu, C. Liu, A. Lei, Chem. Asian J., 2015, 10, 2040.
20 No oxazoline product was obtained under conditions B with Ag2O.
21 Unlike 1, heating 4- to 6-membered cyclic substrates (e.g.
trichloroimidates of cyclohexanol) with 3 equiv of NIS in DCE gave a
complex mixture of unreacted starting materials, oxazolines and other
products. No Cβ iodinated intermediates (see VIII) were identified. We
speculate that the iodinated intermediates are difficult to form, or are
highly reactive. If Cβ iodinated intermediates are formed, Ag2O might
also promote cyclization as an iodide scavenger via either SN2 (for trans-
iodinated) or SN1 (for cis-iodinated) pathways to give oxazoline
products. At the current stage, pathway a cannot be completely ruled
out.
5 For selected reviews on the Barton reaction: (a) G. Majetich, K.
Wheless, Tetrahedron, 1995, 51, 7095; (b) Ž. Čeković, Tetrahedron,
2003, 59, 8073.
6 J. I. Concepción, C. G. Francisco, R. Hernández, J. A. Salazar, E. Suárez,
Tetrahedron Lett., 1984, 25, 1953.
7 For selected reviews on Hoffmann-Löffler-Freytag reaction: (a) M. E.
Wolff, Chem. Rev., 1963, 63, 55; (b) R. S. Neale, Synthesis, 1971, 1; (c)
P. Mackiewicz, R. Furstoss, Tetrahedron, 1978, 34, 3241.
8 For selected application and modification of HLF reaction: (a) E. J.
Corey, W. R. Hertler, J. Am. Chem. Soc., 1958, 80, 2903; (b) L. R.
4 | J. Name., 2012, 00, 1-3
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