Rhodium-Catalyzed Cyclization of O,ω-Unsaturated Alkoxyamines: Formation of Oxygen-Containing Heterocycles

Article abstract of DOI:10.1002/anie.201710895

O,ω-Unsaturated N-tosyl alkoxyamines undergo unexpected Rh^III-catalyzed intramolecular cyclization by oxyamination to produce oxygen-containing heterocycles. Mechanistic studies show that an aziridine intermediate seems to be responsible for the formation of the heterocycles, possibly via a Rh^V species.

Full text of DOI:10.1002/anie.201710895

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International Edition: DOI: 10.1002/anie.201710895
German Edition: DOI: 10.1002/ange.201710895
Cyclizations
Rhodium-Catalyzed Cyclization of O,w-Unsaturated Alkoxyamines:
Formation of Oxygen-Containing Heterocycles
Julien Escudero, Vꢀronique Bellosta, and Janine Cossy*
Abstract: O,w-Unsaturated N-tosyl alkoxyamines undergo
unexpected RhIII-catalyzed intramolecular cyclization by oxy-
amination to produce oxygen-containing heterocycles. Mech-
anistic studies show that an aziridine intermediate seems to be
responsible for the formation of the heterocycles, possibly via
a RhV species.
reactivity of the N-tosyl O,w-unsaturated alkoxyamines C in
the presence of a rhodium(III) catalyst was examined with the
aim of the obtaining isoxazolidines D. However, the first
experimental trials only led to the functionalized oxygen-
containing heterocycles E, resulting from a formal intra-
molecular oxyamination (Scheme 1b).
A literature search showed that there are three different
ways to realize intramolecular oxyamination of a double
bond: a) by cyclization of unsaturated nitrogen-containing
compounds in the presence of an external oxygen source
(which leads to the formation of a nitrogen-containing
heterocycle);[8] b) by cyclization of unsaturated oxygen-con-
taining compounds in the presence of an external nitrogen
source (resulting in the formation of an oxygen-containing
heterocycle);[9] c) by cyclization of unsaturated compounds
O
ver the last decades, metal-catalyzed reactions have
proven to be useful tools for accessing complex molecules
in a limited number of steps and with high efficiency. In this
À
context, C H activation has become a very powerful method
for functionalizing a diversity of molecules.[1] Among the
À
different metal catalysts used in C H activations, rhodium-
(III)[2] has been extensively studied and a number of rhodium-
2
[3,4]
3
[5]
À
À
(III)-catalyzed C(sp ) H,
activations have been reported. For our part, we have
demonstrated that rhodium(III) could be used to trigger an
as well as C(sp ) H bond
À
that contain a N O bond, which is cleaved during the
process.[10] It is worth noting that there are many more reports
on nitrogen-based (a)[8] than oxygen-based (b)[9] intramolec-
ular oxyaminations. Furthermore, the examples of intramo-
3
À
intramolecular allylic C(sp ) H amination of unsaturated N-
tosylamides such as A (Scheme 1a).[6] Later on, Rovis et al.
3
À
À
took advantage of this rhodium(III)-catalyzed allylic C(sp )
lecular oxyaminations from compounds containing an N O
H bond activation to produce azabicyclic structures by adding
bond (c)[10] are quite rare and they always involve the
formation of an oxygen-substituted nitrogen-containing het-
erocycle. The formation of a saturated oxygen-containing
heterocycle of type E from an O,w-unsaturated alkoxyamine
is, to the best of our knowledge, the first example of such
a transformation.
an exogenous internal alkyne.[7] Based on these results, the
The N-tosyl O,w-unsaturated alkoxyamine 1a[11] was
selected as a model substrate and treated under the reaction
conditions that we developed previously,[6] for example,
[Cp*Rh(MeCN)3](SbF6)2 (5 mol%) in the presence of Cu-
(OAc)2·H2O (2.1 equiv) in 1,2-dichloroethane (DCE) at 958C
for 2.5 hours (Scheme 2). Under these reaction conditions, 1a
was transformed into the functionalized tetrahydrofuran 2a in
60% yield and no trace of the expected isoxazolidine 2a’ was
detected. It is worth mentioning that trace amounts of N-
tosylamine were detected in the reaction media.
Among the solvents tested (DCE, t-AmylOH, 1,4-diox-
ane), DCE appeared to be the best one.[12] Different additives
were used, including CsOAc, NaOAc, Cu(OAc)2·H2O, and
anhydrous Cu(OAc)2, which proved to be the most effective
as the yield of 2a was increased from 60 to 72%[13] (Table 1,
Scheme 1. Rhodium(III)-catalyzed cyclization of N-tosylamides and N-
tosyl O,w-unsaturated alkoxyamines. Ts=4-toluenesulfonyl.
[*] J. Escudero, Prof. V. Bellosta, Prof. J. Cossy
Laboratory of Organic Chemistry, CNRS, ESPCI Paris, PSL Research
University
10 rue Vauquelin 75231 Paris Cedex 05 (France)
E-mail: janine.cossy@espci.fr
Supporting information and the ORCID identification number(s) for
the author(s) of this article can be found under:
https://doi.org/10.1002/anie.201710895.
Scheme 2. Rhodium(III)-catalyzed cyclization of 1a. Cp*=C5Me5,
DCE=1,2-dichloroethane.
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Table 1: Rhodium(III)-catalyzed cyclization of the N-tosyl O,w-unsatu-
rated alkoxyamines 1a–o.[a]
Table 1: (Continued)
Entry
Substrate
Product
Yield [%][b]
14
0[d]
Entry
1
Substrate
Product
Yield [%][b]
72
15
0
[a] See the Supporting Information for general procedure. [b] Yield of
isolated product. [c] p-TsNH2 was the major product. [d] Small amounts
of p-TsNH2 were obtained. n.d.=not determined. TBS=tBuMe2Si.
2
51
3
4
63
entry 1). It is worth noting that the reaction can be performed
with 0.1 equivalents of anhydrous Cu(OAc)2 instead of
2.1 equivalents, but under these reaction conditions the
reaction required more time for completion and the yield
was only 57%. The reaction is general and the results are
reported in Table 1.
trace[c]
It is worth mentioning that a Thorpe–Ingold effect
(Table 1, entries 1–8 versus entries 9 and 10), as well as the
presence of an alkyl substituent at the non-terminal position
of the double bond (entries 11 and 12) were beneficial for the
yield of the tetrahydrofurans. On the contrary, the presence of
a phenyl group at the non-terminal position of the double
bond (entry 13), as well as the substitution at the terminal
position (entries 14 and 15), were detrimental to the forma-
tion of 2.
Whereas low yields in 2c, 2 f, and 2i were obtained from
the corresponding N-tosyl O,w-unsaturated alkoxyamines,
treatment of the analogous N-tosyl O,w-unsaturated alkoxy-
amines 3a, 3b, and 3c (Table 2), possessing a methyl at the
nonterminal position of the double bond, with rhodium(III)
(cat.) and Cu(OAc)2 gave better yields of the cyclized
products 4 (2d traces, 4a 20%; 2g 20%, 4b 52%; 2j 13%,
4c 58%; Tables 1 and 2).
5
6
7
63
54
20[d]
8
9
70[d]
22
Table 2: Rhodium(III)-catalyzed cyclization of the N-tosyl O,w-unsatu-
rated alkoxyamines 3a–c.[a]
10
11
13[d]
78
Entry
Substrate
Product
Yield [%][b]
1
20[c]
12
13
53
2
3
52
58
0[d]
[a] See the Experimental Section for general procedure. [b] Yield of
isolated product. [c] p-TsNH2 was the major product.
2
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Table 3: Application of the rhodium(III)-catalyzed cyclization to the
synthesis of six-membered-ring heterocycles.[a]
We have to point out that the yield of the tetrahydrofuran
also depends on the N-protecting group. The N-tosyl group, as
well as the N-nosyl group allowed formation of the cyclized
product in good yields (Scheme 3). Nonetheless, the presence
of an N-carbamate considerably reduced the yield of the
cyclized product 6b, and the presence of an amide group
completely prevented the formation of 6c.
Entry
Substrate
Product
Yield [%][b]
1
20[c]
2
3
73
78
[a] See the Supporting Information for general procedure. [b] Yield of
isolated product. [c] Small amounts of p-TsNH2 were obtained.
Scheme 3. Influence of the N-protecting group. Boc=tert-butoxycar-
bonyl.
Based on the obtained results, some mechanistic hypoth-
eses can be proposed. At first, a mechanism involving an
With these optimized reaction conditions in hand, the
synthesis of bicyclic compounds was examined as they can be
useful platforms to access biologically active products such as
F, which is an analogue of telaprevir, an inhibitor of the NS3/
4A protease of the hepatitis C infection (Scheme 4).[15] Thus,
the model compound 7a was first treated with RhIII/Cu(OAc)2
and the bicyclic product 8a was isolated in 63% yield with
a d.r. value greater than 98:2.[14] The more complex bicyclic
compound 8b (whose framework is present in F) was formed
from 7b in 63% yield and with a d.r. value greater than
98:2.[14] Worth noting is that the new stereogenic center in 8b,
created during the process, possesses the opposite configu-
ration in comparison to that in compound F.
Interestingly, larger rings can also be accessed, for
example, tetrahydropyran rings. The tetrahydropyran 10a
was obtained, albeit in a low yield of 20%, from the substrate
9b (Table 3, entry 1). As previously observed, the substitution
of the double bond at the non-terminal position allowed
formation of the cyclized products 10b and 10c in better
yields of 73 and 78%, respectively (entries 2 and 3).
À
allylic C H activation by the active rhodium(III) catalyst and
the formation of a p-allyl complex can be ruled out as the
reaction works when two substituents are present a to the
double bond (Table 1, entry 8). It can be supposed that
a complexation of the alkene by the active rhodium(III)
catalyst G, generated in situ, could take place to form the
complex H (Scheme 5). This intermediate could evolve in
three different pathways, thus leading to three different
intermediates, namely I, J, and K. The rhodacycle I could arise
from a nucleophilic attack of the oxygen atom onto the
double bond. The rearrangement of this rhodacycle by
À
À
cleavage of the N O bond and the formation of a C N
bond would produce L which could then evolve to the
oxygen-containing heterocycle E by a ligand exchange with
acetic acid (Scheme 5, pathway a). From H, it is also possible
À
to envisage an oxidative addition of the N O bond to
Scheme 4. Application of the rhodium(III)-catalyzed cyclization to the
synthesis of bicyclic compounds.
Scheme 5. Mechanistic hypotheses.
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rhodium(III) to generate the rhodium(V) nitrene species J.[16]
This nitrene would then be able to react with the alkene to
produce the aziridine K, which would then be opened by
nucleophilic attack of the oxygen atom to produce L
(Scheme 5, pathway b). The hypothetic nitrene intermediate
J could be responsible for the formation of p-TsNH2, which
we observed in some cases. It is worth pointing out that K
could also be formed directly from H by attack of the nitrogen
atom on the activated alkene (Scheme 5, pathway c).
In summary, we have discovered a rhodium(III)-catalyzed
transformation that leads to oxygen-containing heterocycles
from N-tosyl O,w-unsaturated alkoxyamines. This reaction is
probably the result of the ring-opening of an aziridine
intermediate, which could be derived from a rhodium(V)
intermediate or from direct aziridination of a rhodium(III)
species by a sulfonamide moiety. Studies to expand this
reaction to useful synthetic applications are ongoing.
As radicals cannot be excluded, treatment of 1a with the
RhIII/Cu(OAc)2 in the presence of TEMPO was realized.
Under these reaction conditions, only 2a was observed[17] and
no product incorporating a TEMPO unit was detected
(Scheme 6a), thus indicating that probably no radical path-
way is involved in the process. When 1a was treated with
RhIII/Cu(OAc)2 in the presence of diphenylacetylene, which is
able to quench the hypothetic nitrene, only 2a and the dimeric
diphenylacetylene 11 were detected[17] and no product
resulting from a potential nitrene trapping was observed,
which could be due to a faster intramolecular aziridination
rather than intermolecular trapping (Scheme 6b). To verify if
K could be an intermediate in the formation of E, the
synthesis of this latter was undertaken (Scheme 6c). Its
preparation started with the unsaturated alcohol 12 which,
after protection and aziridination, led to 13 (77%). After
deprotection of the silylated alcohol 13 (TBAF, THF, RT,
24 h), no trace of the expected aziridine, bearing a free
alcohol, was observed. Instead, the cyclized product 2k was
isolated as the sole product (67%). This result makes the
aziridine hypothesis relevant as the observed oxyaminated
products would spontaneously form if K was generated in the
reaction mixture.
Acknowledgements
J.E. thanks the Ministꢀre de lꢁEnseignement Supꢂrieur et de
la Recherche (MESR) for a grant.
Conflict of interest
The authors declare no conflict of interest.
Keywords: alkenes · cyclizations ·
oxygen-containing heterocycles · rhodium · synthetic methods
À
[1] For selected reviews on metal-catalyzed C H functionalization,
see: a) B.-J. Li, Z.-J. Shi, Chem. Soc. Rev. 2012, 41, 5588 – 5598;
b) N. Kuhl, M. N. Hopkinson, J. Wencel-Delord, F. Glorius,
Angew. Chem. Int. Ed. 2012, 51, 10236 – 10254; Angew. Chem.
2012, 124, 10382 – 10401; c) J. Yamaguchi, A. D. Yamaguchi, K.
Itami, Angew. Chem. Int. Ed. 2012, 51, 8960 – 9009; Angew.
Chem. 2012, 124, 9092 – 9142; d) J. Wencel-Delord, F. Glorius,
Nat. Chem. 2013, 5, 369 – 375; e) L. Yang, H. Huang, Chem. Rev.
2015, 115, 3468 – 3517; f) T. Gensch, M. N. Hopkinson, F.
Glorius, J. Wencel-Delord, Chem. Soc. Rev. 2016, 45, 2900 –
2936; g) M. Gulꢃas, J. L. MascareÇas, Angew. Chem. Int. Ed.
2016, 55, 11000 – 11019; Angew. Chem. 2016, 128, 11164 – 11184;
h) H. M. L. Davies, D. Morton, J. Org. Chem. 2016, 81, 343 – 350;
i) J. R. Hummel, J. A. Boerth, J. A. Ellman, Chem. Rev. 2017,
117, 9163 – 9227; j) C. G. Newton, S.-G. Wang, C. C. Oliveira, N.
Cramer, Chem. Rev. 2017, 117, 8908 – 8976; k) W. Ma, P.
Gandeepan, J. Li, L. Ackermann, Org. Chem. Front. 2017, 4,
1435 – 1467; l) L. Liu, J. Zhang, Chin. J. Org. Chem. 2017, 37,
1117 – 1126; m) Y. Park, Y. Kim, S. Chang, Chem. Rev. 2017, 117,
9247 – 9301.
À
[2] For recent reviews on rhodium(III)-catalyzed C H functional-
ization, see: a) D. A. Colby, R. G. Bergman, J. A. Ellman, Chem.
Rev. 2010, 110, 624 – 655; b) T. Satoh, M. Miura, Chem. Eur. J.
2010, 16, 11212 – 11222; c) F. W. Patureau, J. Wencel-Delord, F.
Glorius, Aldrichimica Acta 2012, 45, 31 – 41; d) G. Song, F. Wang,
X. Li, Chem. Soc. Rev. 2012, 41, 3651 – 3678; e) D. A. Colby, A. S.
Tsai, R. G. Bergman, J. A. Ellman, Acc. Chem. Res. 2012, 45,
814 – 825; f) N. Kuhl, N. Shrçder, F. Glorius, Adv. Synth. Catal.
2014, 356, 1443 – 1460; g) B. Ye, N. Cramer, Acc. Chem. Res.
2015, 48, 1308 – 1318; h) G. Song, X. Li, Acc. Chem. Res. 2015, 48,
1007 – 1020; i) S.-S. Li, L. Qin, L. Dong, Org. Biomol. Chem.
2016, 14, 4554 – 4570; j) Y. Yang, K. Li, Y. Cheng, D. Wan, M. Li,
Chem. Commun. 2016, 52, 2872 – 2884.
[3] For selected recent examples of rhodium(III)-catalyzed aro-
2
À
matic C(sp ) H activation, see: a) S. Sharma, Y. Oh, N. K.
Scheme 6. Experimental results for mechanism discussion. TBAF=te-
tra-n-butylammonium fluoride, TBDPS=tert-butyldiphenylsilyl,
TEMPO=2,2,6,6-tetramethilpiperidine-1-oxyl, THF=tetrahydrofuran.
Mishra, U. De, H. Jo, R. Sachan, H. S. Kim, Y. H. Jung, I. S. Kim,
J. Org. Chem. 2017, 82, 3359 – 3367; b) S. S. Li, C. F. Liu, G. T.
Zhang, Y. Q. Xia, W. H. Li, L. Dong, Chem. Asian J. 2017, 12,
4
www.angewandte.org
ꢀ 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Chemie
415 – 418; c) G. N. Hermann, C. L. Jung, C. Bolm, J. Mack, H.
J. B. Keister, S. R. Chemler, J. Org. Chem. 2013, 78, 506 – 515;
Hopf, Z.-Y. Xu, J. Mack, K. D. M. Harris, G. Hyett, W. Jones,
Green Chem. 2017, 19, 2520 – 2523; d) X. Zhou, Z. Qi, S. Yu, L.
Kong, Y. Li, W. F. Tian, X. Li, Adv. Synth. Catal. 2017, 359, 1620 –
1625; e) J. Tang, S. Li, Z. Liu, Y. Zhao, Z. She, V. D. Kadam, G.
Gao, J. Lan, J. You, Org. Lett. 2017, 19, 604 – 607; f) S. Y. Hong, J.
Jeong, S. Chang, Angew. Chem. Int. Ed. 2017, 56, 2408 – 2412;
Angew. Chem. 2017, 129, 2448 – 2452; g) W.-W. Ji, E. Lin, Q. Li,
H. Wang, Chem. Commun. 2017, 53, 5665 – 5668; h) D. Das, P.
Poddar, S. Maity, R. Samanta, J. Org. Chem. 2017, 82, 3612 –
3621; i) B. Zhang, B. Li, X. Zhang, X. Fan, Org. Lett. 2017, 19,
2294 – 2297; j) N. S. Upadhyay, J. Jayakumar, C.-H. Cheng,
Chem. Commun. 2017, 53, 2491 – 2494; k) J. Wang, L. Wang, S.
Guo, S. Zha, J. Zhu, Org. Lett. 2017, 19, 3640 – 3643; l) J. M.
Villar, J. Suꢄrez, J. A. Varela, C. Saꢄ, Org. Lett. 2017, 19, 1702 –
1705; m) H. Liu, S. Song, C. Q. Wang, C. Feng, T. P. Loh,
ChemSusChem 2017, 10, 58 – 61; n) T. J. Potter, D. N. Kamber,
B. Q. Mercado, J. A. Ellman, ACS Catal. 2017, 7, 150 – 153; o) Z.
Zhang, M. Tang, S. Han, L. Ackermann, J. Li, J. Org. Chem.
2017, 82, 664 – 672.
g) X. Duan, X. Yang, R. Fang, X. Peng, W. Yu, B. Han, J. Org.
Chem. 2013, 78, 10692 – 10704; h) H. Chen, A. Kaga, S. Chiba,
Org. Lett. 2014, 16, 6136 – 6139; i) H. Radicals, X. Duan, N.
Zhou, R. Fang, X. Yang, W. Yu, B. Han, Angew. Chem. Int. Ed.
2014, 53, 3158 – 3162; Angew. Chem. 2014, 126, 3222 – 3226; j) H.
Zhu, P. Chen, G. Liu, J. Am. Chem. Soc. 2014, 136, 1766 – 1769;
k) F. Xu, L. Zhu, S. Zhu, X. Yan, H. C. Xu, Chem. Eur. J. 2014,
20, 12740 – 12744; l) W. Rao, X. Yin, B. Shi, Org. Lett. 2015, 17,
3758 – 3761; m) G. Liu, L. Li, L. Duan, Y. Li, RSC Adv. 2015, 5,
61137 – 61143; n) H. Zhu, P. Chen, G. Liu, Org. Lett. 2015, 17,
1485 – 1488; o) S. Liang, C.-C. Zeng, X.-G. Luo, F. Ren, H.-Y.
Tian, B.-G. Sun, R. D. Little, Green Chem. 2016, 18, 2222 – 2230;
p) X. Q. Hu, J. Chen, J. R. Chen, D. M. Yan, W. J. Xiao, Chem.
Eur. J. 2016, 22, 14141 – 14146; q) L. Liu, Z. Wang, Green Chem.
2017, 19, 2076 – 2079; r) A. Theodorou, C. G. Kokotos, Adv.
Synth. Catal. 2017, 359, 1577 – 1581.
[9] For oxygen-based intramolecular cyclizations by oxyamination
with external nitrogen sources, see: a) L. V. Desai, M. S. Sanford,
Angew. Chem. Int. Ed. 2007, 46, 5737 – 5740; Angew. Chem.
2007, 119, 5839 – 5842; b) V. A. Schmidt, E. J. Alexanian, J. Am.
Chem. Soc. 2011, 133, 11402 – 11405; c) D. Karila, L. Leman,
R. H. Dodd, Org. Lett. 2011, 13, 5830 – 5833; d) F. C. Sequeira,
S. R. Chemler, Org. Lett. 2012, 14, 4482 – 4485; e) H. Yin, T.
Wang, N. Jiao, Org. Lett. 2014, 16, 2302 – 2305; f) X. Peng, Y.
Deng, X. Yang, L. Zhang, W. Yu, B. Han, Org. Lett. 2014, 16,
4650 – 4653; g) S. Hajra, S. M. S. A. S. M. Aziz, Chem. Commun.
2014, 50, 6913 – 6916; h) L. Zhu, H. Yu, Z. Xu, X. Jiang, L. Lin,
R. Wang, Org. Lett. 2014, 16, 1562 – 1565; i) R. Zhu, S. L.
Buchwald, J. Am. Chem. Soc. 2015, 137, 8069 – 8077; j) B. N.
Hemric, K. Shen, Q. Wang, J. Am. Chem. Soc. 2016, 138, 5813 –
5816; k) R. H. Liu, D. Wei, B. Han, W. Yu, ACS Catal. 2016, 6,
6525 – 6530; l) S. Alazet, F. LeVaillant, S. Nicolai, T. Courant, J.
Waser, Chem. Eur. J. 2017, 23, 9501 – 9504; m) J. Xie, Y. W.
Wang, L. W. Qi, B. Zhang, Org. Lett. 2017, 19, 1148 – 1151.
[4] For selected recent examples of rhodium(III)-catalyzed vinylic
2
À
C(sp ) H activation, see: a) J. Wu, D. Wang, Y. Wan, C. Ma,
Chem. Commun. 2016, 52, 1661 – 1664; b) G. A. M. Jardim, J. F.
Bower, E. N. Da Silva Jfflnior, Org. Lett. 2016, 18, 4454 – 4457;
c) S. Sharma, S. H. Han, Y. Oh, N. K. Mishra, S. H. Lee, J. S. Oh,
I. S. Kim, Org. Lett. 2016, 18, 2568 – 2571; d) S. Sharma, S. H.
Han, H. Jo, S. Han, N. K. Mishra, M. Choi, T. Jeong, J. Park, I. S.
Kim, Eur. J. Org. Chem. 2016, 3611 – 3618; e) S. Sharma, S. H.
Han, Y. Oh, N. K. Mishra, S. Han, J. H. Kwak, S. Y. Lee, Y. H.
Jung, I. S. Kim, J. Org. Chem. 2016, 81, 2243 – 2251; f) X. H. Hu,
X. F. Yang, T. P. Loh, ACS Catal. 2016, 6, 5930 – 5934; g) Y. R.
Han, S. H. Shim, D. S. Kim, C. H. Jun, Org. Lett. 2017, 19, 2941 –
2944; h) Y. Zhao, S. Li, X. Zheng, J. Tang, Z. She, G. Gao, J. You,
Angew. Chem. Int. Ed. 2017, 56, 4286 – 4289; Angew. Chem.
2017, 129, 4350 – 4353.
[5] For selected recent examples of rhodium(III)-catalyzed C(sp )
3
À
À
[10] For intramolecular oxyaminations from N O-bond-containing
H activation, see: a) S. Yu, G. Tang, Y. Li, X. Zhou, Y. Lan, X. Li,
Angew. Chem. Int. Ed. 2016, 55, 8696 – 8700; Angew. Chem.
2016, 128, 8838 – 8842; b) S. Han, J. Park, S. Kim, S. H. Lee, S.
Sharma, N. K. Mishra, Y. H. Jung, I. S. Kim, Org. Lett. 2016, 18,
4666 – 4669; c) S. Yu, Y. Li, L. Kong, X. Zhou, G. Tang, Y. Lan,
X. Li, ACS Catal. 2016, 6, 7744 – 7748; d) C.-M. Chan, Z. Zhou,
W.-Y. Yu, Adv. Synth. Catal. 2016, 358, 4067 – 4074; e) C. Tang,
M. Zou, J. Liu, X. Wen, X. Sun, Y. Zhang, N. Jiao, Chem. Eur. J.
2016, 22, 11165 – 11169; f) J. Wippich, N. Truchan, T. Bach, Adv.
Synth. Catal. 2016, 358, 2083 – 2087; g) W. Hou, Y. Yang, Y. Wu,
H. Feng, Y. Li, B. Zhou, Chem. Commun. 2016, 52, 9672 – 9675;
h) S. Kim, S. Han, J. Park, S. Sharma, N. K. Mishra, H. Oh, J. H.
Kwak, I. S. Kim, Chem. Commun. 2017, 53, 3006 – 3009; i) L.
Kong, X. Zhou, Y. Xu, X. Li, Org. Lett. 2017, 19, 3644 – 3647;
j) B. Liu, P. Hu, X. Zhou, D. Bai, J. Chang, X. Li, Org. Lett. 2017,
19, 2086 – 2089; k) T. Zhou, B. Li, B. Wang, Chem. Commun.
2017, 53, 6343 – 6346; l) C. Yuan, G. Tu, Y. Zhao, Org. Lett. 2017,
19, 356 – 359.
compounds, see: a) M. Noack, R. Gçttlich, Chem. Commun.
2002, 536 – 537; b) G. S. Liu, Y. Q. Zhang, Y. A. Yuan, H. Xu, J.
Am. Chem. Soc. 2013, 135, 3343 – 3346; c) Y. Q. Zhang, Y. A.
Yuan, G. S. Liu, H. Xu, Org. Lett. 2013, 15, 3910 – 3913; d) X.
Ren, Q. Guo, J. Chen, H. Xie, Q. Xu, Z. Lu, Chem. Eur. J. 2016,
22, 18695 – 18699.
[11] For the preparation of the starting materials, see the Supporting
Information.
[12] See the Supporting Information (Table S1).
[13] See the Supporting Information (Table S2).
[14] The observed diastereoselectivity is probably the result of the
minimization of steric interactions within transition states.
[15] F. Bennett, R. G. Lovey, Y. Huang, S. Hendrata, A. K. Saksena,
S. L. Bogen, Y. T. Liu, F. G. Njoroge, S. Venkatraman, K. X.
Chen, M. Sannigrahi, A. Arasappan, V. M. Girijavallabhan, F.
Velazquez, U.S. Patent 0042968/A1, 2007.
[16] For computational studies about rhodium(V) complexes, see:
a) Y. Park, J. Heo, M. H. Baik, S. Chang, J. Am. Chem. Soc. 2016,
138, 14020 – 14029; b) J. Q. Wu, S. S. Zhang, H. Gao, Z. Qi, C. J.
Zhou, W. W. Ji, Y. Liu, Y. Chen, Q. Li, X. Li, H. Wang, J. Am.
Chem. Soc. 2017, 139, 3537 – 3545; c) X. Wang, T. Gensch, A.
Lerchen, C. G. Daniliuc, F. Glorius, J. Am. Chem. Soc. 2017, 139,
6506 – 6512; d) D. L. Davies, S. A. Macgregor, C. L. McMullin,
Chem. Rev. 2017, 117, 8649 – 8709; and references therein.
[17] The products 2a and 11 were identified by GC/MS and NMR
analyses of the crude reaction mixtures but were not isolated.
[6] T. Cochet, V. Bellosta, D. Roche, J.-Y. Ortholand, A. Greiner, J.
Cossy, Chem. Commun. 2012, 48, 10745 – 10747.
[7] A. Archambeau, T. Rovis, Angew. Chem. Int. Ed. 2015, 54,
13337 – 13340; Angew. Chem. 2015, 127, 13535 – 13538.
[8] For selected recent examples of nitrogen-based intramolecular
cyclizations by oxyaminations with external oxygen sources, see:
a) S. D. Karyakarte, T. P. Smith, S. R. Chemler, J. Org. Chem.
2012, 77, 7755 – 7760; b) S. Sanjaya, S. H. Chua, S. Chiba, Synlett
2012, 1657 – 1661; c) B. Han, X. Yang, R. Fang, W. Yu, C. Wang,
X. Duan, S. Liu, Angew. Chem. Int. Ed. 2012, 51, 8816 – 8820;
Angew. Chem. 2012, 124, 8946 – 8950; d) S. Sanjaya, S. Chiba,
Org. Lett. 2012, 14, 5342 – 5345; e) K. Moriyama, Y. Izumisawa,
H. Togo, J. Org. Chem. 2012, 77, 9846 – 9851; f) M. C. Paderes,
Manuscript received: October 23, 2017
Version of record online: && &&, &&&&
Angew. Chem. Int. Ed. 2017, 56, 1 – 6
ꢀ 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
5
These are not the final page numbers!

Angewandte
Communications
Chemie
Communications
Cyclizations
Unexpected reactivity: Functionalized
tetrahydrofurans were unexpectedly
obtained instead of the intended isoxa-
zolidines. The reaction proceeds from N-
tosyl O,w-unsaturated alkoxyamines and
J. Escudero, V. Bellosta,
J. Cossy*
&&&& — &&&&
À
Rhodium-Catalyzed Cyclization of O,w-
Unsaturated Alkoxyamines: Formation of
Oxygen-Containing Heterocycles
a known rhodium(III)-catalyzed allylic C
H activation protocol. The scope and
limitations of this surprising reaction are
described. A mechanism, involving
a rhodium(V) nitrenoid and an aziridina-
tion step, is discussed.
6
www.angewandte.org
ꢀ 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2017, 56, 1 – 6
These are not the final page numbers!