(3+3)-Annulation of Carbonyl Ylides with Donor–Acceptor Cyclopropanes: Synergistic Dirhodium(II) and Lewis Acid Catalysis

Article abstract of DOI:10.1002/anie.201814409

The first (3+3)-annulation process of donor–acceptor cyclopropanes using synergistic catalysis is reported. The Rh₂(OAc)₄-catalyzed decomposition of diazo carbonyl compounds generated carbonyl ylides in situ. These 1,3-dipoles were c

Full text of DOI:10.1002/anie.201814409

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Accepted Article
Title: (3+3)-Annulation of Carbonyl Ylides with Donor-Acceptor
Cyclopropanes: Synergistic Dirhodium(II) and Lewis Acid
Catalysis
Authors: Daniel B. Werz, Martin Petzold, and Peter G. Jones
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To be cited as: Angew. Chem. Int. Ed. 10.1002/anie.201814409
Angew. Chem. 10.1002/ange.201814409
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10.1002/anie.201814409
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(3+3)-Annulation of Carbonyl Ylides with Donor-Acceptor
Cyclopropanes: Synergistic Dirhodium(II) and Lewis Acid
Catalysis
Martin Petzold,[a] Peter G. Jones[b] and Daniel B. Werz*[a]
Dedicated to Professor Hans-Ulrich Reißig on the occasion of his 70th birthday
Abstract: The first (3+3)-annulation process of donor-acceptor
cyclopropanes using synergistic catalysis is reported. The Rh2(OAc)4-
catalyzed decomposition of diazo carbonyl compounds generated
carbonyl ylides in situ. These 1,3-dipoles were converted with donor-
acceptor cyclopropanes, activated by Lewis acid catalysis, to afford
multiply substituted pyran scaffolds in high yield and
diastereoselectivity. Extensive optimization studies enabled access to
9-oxabicyclo[3.3.1]nonan-2-one and 10-oxabicyclo[4.3.1]decen-2-ol
cores, exploiting solvent effects on intermediate reactivity.
three-membered rings are relatively inert, we expected that a
second catalyst, a Lewis acid, would be required to activate this
second component. Only the use of two distinct catalysts,
independently activating the two starting materials (i.e. a
synergistic catalytic approach), should allow the desired
transformation in a highly efficient manner.[15]
The efficient one-step synthesis of complex oligocyclic scaffolds
from simple building blocks has fascinated organic chemists for
decades. Cycloadditions and rearrangements – often combined
in a domino fashion – are prime examples of access to molecular
complexity in a single synthetic step.[1] Besides alkenes and
alkynes, which are the most prominent systems to undergo
cycloaddition reactions, donor-acceptor (D-A) cyclopropanes
have in numerous cases been successfully involved in such
transformations. Their use as 1,3-zwitterionic synthons is
promoted by their high strain energy and by the polarized bond
between the carbon atoms bearing the donor and the acceptor
moiety. After seminal work in this field by Wenkert and Reissig
some 30 to 40 years ago, the field has vastly expanded, especially
during the last decade, leading to novel protocols of
rearrangements, cycloadditions and ring-opening reactions.[2,3]
One focus has been the development of (3+n) cycloaddition
reactions affording five-, six- and seven-membered rings (n = 2,
3, 4). Most of the (1,n)-dipoles that have been inserted are stable
Scheme 1. Literature-known (3+3)-annulation reactions of D-A cyclopro-
panes[8,10,11] and our work using synergistic transition metal and Lewis acid
catalysis.
compounds
(e.g.
aldehydes,[4]
imines,[5]
allenes,[6]
thiocarbonyls,[7] azides,[8] nitrones,[9] diaziridines; Scheme 1A[10]
)
or can be generated by the stoichiometric addition of base from a
stable precursor (e.g. nitrile imines; Scheme 1B).[11] To the best
of our knowledge, the reaction of D-A cyclopropanes with 1,3-
dipoles generated by transition metal catalysis as fleeting
intermediates has not been reported yet (Scheme 1C).[12]
At the beginning of our studies, we chose D-A cyclopropane
1a and diazo compound 2a as model substrates to determine the
optimal conditions for this synergistic (3+3) cycloaddition. As
expected, two catalysts are required for
a
successful
Our idea was to use the dirhodium(II)-catalyzed
decomposition of diazo carbonyl compounds to generate carbonyl
ylides in situ,[13,14] which are then employed in a (3+3)-
cycloaddition reaction with D-A cyclopropanes. Because the
transformation (Table 1, entries 1-2). However, even the use of
both a Rh(II) and a Lewis acid catalyst only induces the reaction
in the presence of molecular sieves (entries 3-5). The Lewis acid
Sc(OTf)3 proved to be more suitable than Yb(OTf)3. Surprisingly,
Sc(OTf)3 doped with 5% of Yb(OTf)3 gave about a threefold
increase in yield to 32% and a much higher diastereoselectivity of
up to 9:1 (entries 4, and 6).[16] However, better yields were only
achievable by changing the solvent. Whereas in THF no reaction
was observed (entry 7), toluene boosted the yield to 93%, but with
only moderate diastereoselectivity (entries 8-10). The optimal
reaction temperature was found to be 30 °C; higher temperatures
(70 °C) shut down the desired transformation (entry 11). More
[a] M.Sc. M. Petzold, Prof. Dr. D. B. Werz
Technische Universität Braunschweig, Institute of Organic Chemistry,
Hagenring 30, 38106 Braunschweig (Germany)
E-mail: d.werz@tu-braunschweig.de, Homepage: http://www.werzlab.de
[b] Prof. Dr. P. G. Jones
Technische Universität Braunschweig, Institute of Inorganic and Analytical
Chemistry, Hagenring 30, 38106 Braunschweig (Germany)
Supporting information for this article is given via a link at the end of the
document.
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10.1002/anie.201814409
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elaborate dirhodium(II) catalysts such as Rh2(pfb)4 and Rh2(cap)4
only resulted in 61-62% yield (entries 12-13, for full details on the
optimization studies, see Supporting Information).
Table 1. Optimization of the reaction conditions.[a]
Entry
1
2
3[b]
4
Rh(II) cat.
Rh2(OAc)4
-
Lewis acid
-
Solvent
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
THF
PhMe
PhMe
PhMe
PhMe
PhMe
PhMe
T [°C]
RT
RT
RT
RT
RT
RT
RT
RT
0
3a [%]
0
0
0
12
5
32
0
83
52
93
0
dr
-
-
Sc(OTf)3
Sc(OTf)3
Sc(OTf)3
Yb(OTf)3
Sc(OTf)3
Sc(OTf)3
Sc(OTf)3
Sc(OTf)3
Sc(OTf)3
Sc(OTf)3
Sc(OTf)3
Sc(OTf)3
Rh2(OAc)4
Rh2(OAc)4
Rh2(OAc)4
Rh2(OAc)4
Rh2(OAc)4
Rh2(OAc)4
Rh2(OAc)4
Rh2(OAc)4
Rh2(OAc)4
Rh2(pfb)4
Rh2(cap)4
4.4:1
7.1:1
9.1:1
-
4.0:1
5.0:1
3.6:1
-
5
6[c]
7[c]
8[c]
9[c,d]
10[c]
11[c]
12[c]
13[c]
30
70
30
30
61
62
3.4:1
4.0:1
[a]
Reaction conditions: 1a (150 µmol), Sc(OTf)3 (10 mol%), Rh2L4 (2 mol%),
MS 4Å (60 mg), 1a was dissolved in 2 mL of solvent and a solution of 2a
(100 µmol) in 1 mL of solvent was added within 1 h. [b] No MS 4Å was added.
[c]
[d]
Sc(OTf)3 was doped with Yb(OTf)3 (0.5 mol%).
20 mol% Sc(OTf)3 and
1 mol% Yb(OTf)3 were used. Isolated yields. THF = tetrahydrofuran, pfb =
perfluorobutyrate, cap = ε-caprolactamate, L = Ligand.
With the optimized reaction conditions in hand, we
investigated the scope of this (3+3) cycloaddition reaction. First,
a variety of D-A cyclopropanes were investigated (Scheme 2).
Phenyl donors with electron-donating substituents (1a, 1b, 1c)
yielded the desired products 3a-3c in good to excellent yields.
More extended π-systems such as naphthyl (1e) and heterocyclic
donors such as thienyl (1f) were also tolerated, whereas more
electron-withdrawing fluoro, chloro and bromo substituents
decreased the performance of the reaction significantly (3g-i).
Attempts to involve D-A cyclopropanes with strongly electron-
withdrawing 4-nitro- or 4-cyanoaryl moieties and non-aromatic
donors such as vinyl residues in this protocol were unsuccessful.
In addition, the carbonyl ylide substrates were varied
(Figure 1). Extended π-systems (3j), heterocycles (3l, 3m) and
electron-withdrawing substituents attached to the aromatic
backbone (3k) work in moderate to good yields. Substrates
lacking an aromatic backbone were not successfully converted
into the respective oxygen-bridged carbocycles 3.
Scheme 2. Scope of the (3+3)-annulation for various D-A cyclopropanes 1. [a]
1
(150 µmol) and 2 (100 µmol) were used. [b] 1 (100 µmol) and 2 (150 µmol) were
used. The annotation a represents the axial and b the equatorial isomer.
To obtain an insight into the mechanism, the reaction of 2a
was performed with enantioenriched D-A cyclopropane (S)-1d
(96% ee). The resulting annulation products 3da and 3db show
93% and 94% ee, respectively. The absolute configuration of 3db
(5R, 8R, 9R) was elucidated by X-ray diffraction analysis; it was
found to be the respective inversion product.[17] These results
suggest a stereospecific annulation process (Scheme 3; for
further mechanistic investigations see Supporting Information).
Figure 1. Scope of the (3+3)-annulation with respect to different carbonyl ylides.
[a] 1 (150 µmol) and 2 (100 µmol) were used. [b] 1 (100 µmol) and 2 (150 µmol)
were used. The annotation a represents the axial and b the equatorial isomer.
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Table 2. Readjustment of the reaction conditions.[a]
Entry
1
2
3[b]
4[c]
5[d]
Solvent
PhMe
PhMe
T [°C]
30
50
30
30
6a [%]
37
37
0
70
dr
>20:1
>20:1
-
>20:1
>20:1
PhMe/THF (1:1)
CH2Cl2
CH2Cl2
30
97
[a] Reaction conditions: To MS 4Å (60 mg), Rh2(OAc)4 (2 mol%),
Sc(OTf)3 (20 mol%) and Yb(OTf)3 (1 mol%) a solution of 1a
(150 µmol) in 2 mL of solvent was added. A solution of 5
[b]
(100 µmol) in 1 mL of solvent was added within 5 h.
1a
(100 µmol) and 5 (150 µmol) were used. [c] 1a (200 µmol) were
used. No work-up was performed. Yields represent isolated
[d]
yields. THF = tetrahydrofuran.
The strikingly different diastereoselectivities for
both transformations are probably associated with
solvent effects, which strongly influence reactivity and
appearance of intermediate species (Da or Db) that
are present. It is known that CH2Cl2, rather than
toluene, stabilizes the formation of metallacarbenoid
species.[18] Carbonyl ylides derived from 2a and 5,
respectively, differ strongly in their stability. The former
one is completely conjugated, the latter is not. Non-
conjugated ylides of type Db are supposed to undergo
fast decomposition suggesting species such as Da
being the important intermediates. Since Da is more
sterically congested than Db, higher diastereose-
lectivities for the formation of 6 are observed (for
details, see Supporting Information).
Scheme 3. Plausible mechanism for the synergistic (3+3)-annulation reaction of D-A
cyclopropanes 1 with in situ generated carbonyl ylides C.
Additional trapping experiments of the active species
generated from 2a were performed in the absence of both
cyclopropane 1 and Lewis acid. They delivered alkylated and non-
alkylated isochromanones 4a and 4b, respectively. From these
results we infer that species D merge the outer carbenoid cycle
with the inner D-A cyclopropane cycle as depicted in Scheme 3.
Once formed from metallacarbenoid species C, they react with
activated D-A cyclopropane G to afford E, followed by ring-closure
to F.[16] The inner cycle completes after release of product H.
Minor changes to the initial procedure (Table 2) together
with a homolog of the diazo starting material allowed access to
nine-membered oxygen-bridged products. Surprisingly, the
reaction of D-A cyclopropanes 1 with diazo compound 5 furnishes
the products 6 as cyclononenoles (Scheme 4), in contrast to the
expected cyclononanones, though in high yield and excellent
diastereoselectivity.
In contrast to the reaction with diazo compounds 2, it turned out
to be more tolerant towards electron-withdrawing substituents
and heteroatom donors. Notably, halogen-substituted donors (6d-
Scheme 4. Scope of oxygen-bridged cyclononenoles 6 via (3+3)-annulation. 1
(200 µmol) and 5 (100 µmol) were used.
6f) as well as heterocyclic or nitrogen donors as commonly used
by Waser (6g and 6i) were tolerated.[4b,5c,7d]
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[4] a) J. Sabbatani, N. Maulide, Angew. Chem. Int. Ed. 2016, 55, 6780; Angew.
Chem. 2016, 128, 6892; b) F. Benfatti, F. de Nanteuil, J. Waser, Chem.
Eur. J. 2012, 18, 4844; c) A. G. Smith, M. C. Slade, J. S. Johnson, Org.
Lett. 2011, 13, 1996; d) A. T. Parsons, J. S. Johnson, J. Am. Chem. Soc.
2009, 131, 3122; e) P. D. Pohlhaus, S. D. Sanders, A. T. Parsons, W. Li,
J. S. Johnson, J. Am. Chem. Soc. 2008, 130, 8642.
In summary, we have developed a protocol for the reaction of D-A
cyclopropanes and carbonyl ylides. To realize this transformation,
we have made use of synergistic dirhodium and Lewis acid
catalysis; the former catalyst generated carbonyl ylides in situ
from corresponding diazo compounds, while Sc(OTf)3 activated
the three-membered ring. 9-Oxabicyclo[3.3.1]nonan-2-one and
10-oxabicyclo[4.3.1]decene-2-ol cores have been obtained in
moderate to excellent yields and diastereoselectivity. A strong
solvent influence with respect to the stereochemical outcome was
observed, suggesting different reactive species as key
intermediates. Trapping experiments and investigations with
highly enantioenriched D-A cyclopropane led us to a plausible
mechanistic concept.
[5] a) L. K. B. Garve, P. G. Jones, D. B. Werz, Angew. Chem. Int. Ed. 2017,
56, 9226; Angew. Chem. 2017, 129, 9354; b) L. K. B. Garve, A. Kreft, P.
G. Jones, D. B. Werz, J. Org. Chem. 2017, 82, 9235; c) J. Preindl, S.
Chakrabarty, J. Waser, Chem. Sci. 2017, 8, 7112; d) K. Verma, P.
Banerjee, Adv. Synth. Catal. 2017, 359, 3848.
[6] a) R. Tombe, T. Iwamoto, T. Kurahashi, S. Matsubara, Synlett 2014, 25,
2281; b) Z. Wang, J. Ren, Z. Wang, Org. Lett. 2013, 15, 5682.
[7] a) A. U. Augustin, M. Busse, P. G. Jones, D. B. Werz, Org. Lett. 2018, 20,
820; b) Y. Matsumoto, D. Nakatake, R. Yazaki, T. Ohshima, Chem. Eur.
J. 2018, 24, 6062; c) A. U. Augustin, M. Sensse, P. G. Jones, D. B. Werz,
Angew. Chem. Int. Ed. 2017, 56, 14293; Angew. Chem. 2017, 129, 14481;
d) S. Racine, B. Hegedüs, R. Scopelliti, J. Waser, Chem. Eur. J. 2016, 22,
11997.
Acknowledgments
This research was supported by the European Research Council
(ERC Consolidator Grant “GAINBYSTRAIN” to D.B.W).
[8] a) K. L. Ivanov, E. V. Villemson, E. M. Budynina, O. A. Ivanova, I. V.
Trushkov, M. Y. Melnikov, Chem. Eur. J. 2015, 21, 4975; b) H.-H. Zhang,
Y.-C. Luo, H.-P. Wang, W. Chen, P.-F. Xu, Org. Lett. 2014, 16, 4896; c)
M. R. Emmett, H. K. Grover, M. A. Kerr, J. Org. Chem. 2012, 77, 6634.
[9] a) C. D. Schmidt, J. Kaschel, T. F. Schneider, D. Kratzert, D. Stalke, D. B.
Werz, Org. Lett. 2013, 15, 6098; b) I. S. Young, M. A. Kerr, Angew. Chem.
Int. Ed. 2003, 42, 3023; Angew. Chem. 2003, 115, 3131.
Conflict of interest
The authors declare no conflict of interest.
Keywords: cyclopropanes • cycloaddition • carbonyl ylides •
donor-acceptor systems • synergistic catalysis
[10] a) A. O. Chagarovskiy, V. S. Vasin, V. V. Kuznetsov, O. A. Ivanova, V. B.
Rybakov, A. N. Shumsky, N. N. Makhova, I. V. Trushkov, Angew. Chem.
Int. Ed. 2018, 57, 10338; Angew. Chem. 2018, 130, 10495.
[1] a) Q.-Q. Cheng, Y. Deng, M. Lankelma, M. P. Doyle, Chem. Soc. Rev.
2017, 46, 5425; b) R. J. Harris, R. A. Widenhoefer, Chem. Soc. Rev. 2016,
45, 4533; c) T. Hashimoto, K. Maruoka, Chem. Rev. 2015, 115, 5366; d)
K. V. Gothelf, K. A. Jørgensen, Chem. Rev. 1998, 98, 863.
[11] a) L. K. B. Garve, M. Petzold, P. G. Jones, D. B. Werz, Org. Lett. 2016,
18, 564; b) A. Ghosh, A. K. Pandey, P. Banerjee, J. Org. Chem. 2015, 80,
7235; c) S. J. Gharpure, L. N. Nanda, M. K. Shukla, Org. Lett. 2014, 16,
6424.
[2] a) S. J. Gharpure, L. N. Nanda, Tetrahedron Lett. 2017, 58, 711; b) M. A.
Cavitt, L. H. Phun, S. France, Chem. Soc. Rev. 2014, 43, 804; c) T. F.
Schneider, J. Kaschel, D. B. Werz, Angew. Chem. Int. Ed. 2014, 53, 5504;
Angew. Chem. 2014, 126, 5608; d) C. A. Carson, M. A. Kerr, Chem. Soc.
Rev. 2009, 38, 3051; e) M. Yu, B. L. Pagenkopf, Tetrahedron 2005, 61,
321; f) H.-U. Reissig, R. Zimmer, Chem. Rev. 2003, 103, 1151; g) H.-U.
Reissig, E. Hirsch, Angew. Chem. Int. Ed. Engl. 1980, 19, 813; Angew.
Chem. 1980, 92, 839; h) E. Wenkert, M. E. Alonso, B. L. Buckwalter, K. J.
Chou, J. Am. Chem. Soc. 1977, 99, 4778.
[12] a) H. M. L. Davies, D. Morton, ACS Cent. Sci. 2017, 3, 936; b) A.
DeAngelis, R. Panish, J. M. Fox, Acc. Chem. Res. 2016, 49, 115; c) J. He,
L. G. Hamann, H. M. L. Davies, R. E. J. Beckwith, Nat. Commun. 2015, 6,
5943; d) H. M. L. Davies, J. S. Alford, Chem. Soc. Rev. 2014, 43, 5151; e)
B. T. Parr, H. M. L. Davies, Nat. Commun. 2014, 5, 4455; f) R. Cohen, B.
Rybtchinski, M. Gandelman, H. Rozenberg, J. M. L. Martin, D. Milstein, J.
Am. Chem. Soc. 2003, 125, 6532.
[3] a) A. Kreft, A. Lücht, J. Grunenberg, P. G. Jones, D. B. Werz, Angew.
Chem. Int. Ed. 2019, 56, 1955-1959; Angew. Chem. 2019, 131, 1975-
1979; b) S. Das, C. G. Daniliuc, A. Studer, Angew. Chem. Int. Ed. 2018,
57, 4053; Angew. Chem. 2018, 130, 4117; c) R. A. Novikov, D. A. Denisov,
K. V. Potapov, Y. V. Tkachev, E. V. Shulishov, Y. V. Tomilov, J. Am. Chem.
Soc. 2018, 140, 14381; d) S. Das, C. G. Daniliuc, A. Studer, Angew. Chem.
Int. Ed. 2017, 56, 11554; Angew. Chem. 2017, 129, 11712; e) A. Lücht, L.
J. Patalag, A. U. Augustin, P. G. Jones, D. B. Werz, Angew. Chem. Int.
Ed. 2017, 56, 10587; Angew. Chem. 2017, 129, 10723; f) R. A. Novikov,
A. V. Tarasova, D. A. Denisov, D. D. Borisov, V. A. Korolev, V. P. Timofeev,
Y. V. Tomilov, J. Org. Chem. 2017, 82, 2724; g) L. K. A. Pilsl, T. Ertl, O.
Reiser, Org. Lett. 2017, 19, 2754; h) S. Das, C. G. Daniliuc, A. Studer, Org.
Lett. 2016, 18, 5576; i) T. Kaicharla, T. Roy, M. Thangaraj, R. G. Gonnade,
A. T. Biju, Angew. Chem. Int. Ed. 2016, 55, 10061; Angew. Chem. 2016,
128, 10215; j) J. Wallbaum, L. K. B. Garve, P. G. Jones, D. B. Werz, Chem.
Eur. J. 2016, 22, 18756; k) Y. Xia, L. Lin, F. Chang, Y. Liao, X. Liu, X.
Feng, Angew. Chem. Int. Ed. 2016, 55, 12228; Angew. Chem. 2016, 128,
12416; l) R. A. Novikov, Y. V. Tomilov, Mendeleev Commun. 2015, 25, 1;
m) Y. Xia, X. Liu, H. Zheng, L. Lin, X. Feng, Angew. Chem. Int. Ed. 2015,
54, 227; Angew. Chem. 2015, 127, 229; n) H. Xu, J.-L. Hu, L. Wang, S.
Liao, Y. Tang J. Am. Chem. Soc. 2015, 137, 8006; o) L. K. B. Garve, P.
Barkawitz, P. G. Jones, D. B. Werz, Org. Lett. 2014, 16, 5804; p) Y.-Y.
Zhou, L.-J. Wang, J. Li, X.-L. Sun, Y. Tang J. Am. Chem. Soc. 2012, 134,
9066; q) C. Sparr, R. Gilmour, Angew. Chem. Int. Ed. 2011, 50, 8391;
Angew. Chem. 2011, 123, 8541.
[13] a) A. Ford, H. Miel, A. Ring, C. N. Slattery, A. R. Maguire, M. A. McKervey,
Chem. Rev. 2015, 115, 9981; b) D. M. Hodgson, Pierard, Françoise Y. T.
M., P. A. Stupple, Chem. Soc. Rev. 2001, 30, 50; c) M. P. Doyle, D. C.
Forbes, Chem. Rev. 1998, 98, 911; d) T. Ye, M. A. McKervey, Chem. Rev.
1994, 94, 1091.
[14] a) Y. Deng, L. A. Massey, Y. A. Rodriguez Núñez, H. Arman, M. P. Doyle,
Angew. Chem. Int. Ed. 2017, 56, 12292; Angew. Chem. 2017, 129, 12460;
b) Q.-Q. Cheng, J. Yedoyan, H. Arman, M. P. Doyle, Angew. Chem. 2016,
128, 5663; Angew. Chem. Int. Ed. 2016, 55, 5573; c) M. C. Nakhla, C.-W.
Lee, J. L. Wood, Org. Lett. 2015, 17, 5760; d) N. Shimada, T. Oohara, J.
Krishnamurthi, H. Nambu, S. Hashimoto, Org. Lett. 2011, 13, 6284; e) S.
Torssell, P. Somfai, Adv. Synth. Catal. 2006, 348, 2421; f) A. P. Molchanov,
V. V. Diev, J. Magull, D. Vidovi, S. I. Kozhushkov, A. de Meijere, R. R.
Kostikov, Eur. J. Org. Chem. 2005, 2005, 593; g) A. E. Russell, J. Brekan,
L. Gronenberg, M. P. Doyle, J. Org. Chem. 2004, 69, 5269.
[15] a) D. R. Pye, N. P. Mankad, Chem. Sci. 2017, 8, 1705; b) C. K. Prier, D.
A. Rankic, D. W. C. MacMillan, Chem. Rev. 2013, 113, 5322; c) A. E. Allen,
D. W. C. MacMillan, Chem. Sci. 2012, 2012, 633.
[16] We anticipate that Yb(OTf)3 increases the electrophilicity of the benzylic
position in intermediate E, thus directing the reaction to the desired
intermediate F, since no formation of open-chain products was observed.
[17] Details of X-ray structure determinations are given in the Supporting
Information.
Additionally,
CCDC 184659-184665
contain
the
supplementary crystallographic data for this paper. These data are
provided free of charge by The Cambridge Crystallographic Data Centre.
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[18] a) J. Wang, J. Kubicki, H. Peng, M. S. Platz, J. Am. Chem. Soc. 2008, 130,
6604; b) D. M. Hodgson, J. M. Bailey, C. Villalonga-Barber, M. G. B. Drew,
T. Harrison, J. Chem. Soc., Perkin Trans. 1 2000, 3432.
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Angewandte Chemie International Edition
COMMUNICATION
COMMUNICATION
Martin Petzold, Peter G. Jones, Daniel
B. Werz*
Page No. – Page No.
(3+3)-Annulation of Carbonyl Ylides
with Donor-Acceptor Cyclopropanes:
Synergistic Dirhodium(II) and Lewis
Acid Catalysis
Best of both worlds: A synergistic catalytic approach for the construction of multiply
substituted pyrans is reported. It merges cyclopropane with carbene chemistry. The
synthesis of [3.3.1]- and [4.3.1]-core structures under mild conditions in moderate to
excellent yields is demonstrated and a plausible mechanism is suggested.
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