Palladium-Catalyzed Dearomative syn-1,4-Carboamination

Article abstract of DOI:10.1021/jacs.7b11663

A dearomative 1,4-carboamination of arenes has been achieved using arenophile cycloaddition and subsequent palladium-catalyzed substitution with nonstabilized lithium enolates. This protocol delivers products with exclusive syn-1,4-selectivity and can be also conducted in an asymmetric fashion. The method allows rapid dearomative difunctionalization of simple aromatic compounds into functional small molecules amenable to further diversification.

Full text of DOI:10.1021/jacs.7b11663

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Palladium-Catalyzed Dearomative syn-1,4-Carboamination
Mikiko Okumura, Alexander S. Shved, and David Sarlah
J. Am. Chem. Soc., Just Accepted Manuscript • DOI: 10.1021/jacs.7b11663 • Publication Date (Web): 28 Nov 2017
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Palladium-Catalyzed Dearomative syn-1,4-Carboamination
Mikiko Okumura, Alexander S. Shved, and David Sarlah*
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Roger Adams Laboratory, Department of Chemistry, University of Illinois, Urbana, Illinois 61801, United States.
Supporting Information Placeholder
heterobicycles, they could operate under mechanistically distinct
regime, proceeding through an oxidative addition and allylic
substitution process. Overall, this would result in a dearomative
aminofunctionalization, a highly step- and atom-economical
transformation that would deliver syn-1,4-carboaminated products
directly from simple arenes.
ABSTRACT: A dearomative 1,4-carboamination of arenes has
been achieved using arenophile cycloaddition and subsequent
palladium-catalyzed substitution with nonstabilized lithium
enolates. This protocol delivers products with exclusive syn-1,4-
selectivity and can be also conducted in an asymmetric fashion. The
method allows rapid dearomative difunctionalization of simple
aromatic compounds into functional small molecules amenable to
further diversification.
Scheme 1. Dearomative Aminofunctionalizations.
The development of functionalization methods that convert
simple building blocks to more complex, value-added compounds
is at the heart of contemporary organic synthesis. Particularly,
functional elaboration of arenes has received significant attention,1
given their ample availability and application within all areas of
molecular sciences. While most of the recent focus has been in the
2
area of C–H activation, functionalization with concurrent loss of
3
aromatization (i.e. dearomative functionalization) is significantly
less developed, despite the unique synthetic and functional
versatility of the products.4
Alternatively, formal dearomative difunctionalization of
polynuclear arenes has been established using transition-metal-
catalyzed ring-opening reactions of heterobicyclic alkenes.5
Accordingly, azabenzonorbornadienes can be opened with a
variety of nucleophiles delivering mainly 1,2-aminofunctionalized
6
hydronaphthalenes (Scheme 1A). While exceptionally powerful,
and with notable applications in natural product and drug
synthesis, these transformations do require more elaborate starting
precursors that are prepared through benzyne-pyrrole cycloaddition
chemistry. Here, we document dearomative carboamination
involving visible-light-mediated arene-arenophile cycloaddition
and in situ Pd-catalyzed substitution of the resulting cycloadducts
7
At the outset of our work, we focused on the identification of
suitable reaction conditions that would readily elaborate
naphthalene (1) to the corresponding carboaminated product 4
using N-methyl-1,2,4-triazoline-3,5-dione (MTAD, 2) as an
arenophile and ketone 3 as an enolate source (Table 1). Initial
investigations (see Supporting Information for full details) revealed
(Scheme 1B). The reaction delivers syn-1,4-difunctionalized
2
that bidentate ligands in combination with Pd(dba) as Pd source
products directly from feedstock or readily available arenes with
the lithium enolate employed as nucleophiles. In addition, this
process can be used for asymmetric desymmetrization, delivering
products with high enantioselectivity. Finally, the synthetic utility
of the method is demonstrated by a rapid preparation of
functionalized small molecules.
were critical for good conversions. Thus, conducting the
cycloaddition reaction at –50 °C in dichloromethane followed by
subsequent addition of the lithium enolate of 3, generated using
2
LDA, and catalyst [Pd(dba) /dppb] provided the product 4 in 43%
yield (Table 1, entry 1). Temperature played a significant role, as
conducting the substitution step at –30 °C resulted in noticeably
higher yield (72%, entry 2). However, cycloreversion of the
cycloadduct was observed at higher temperatures (–10 °C),
providing moderate yield of the desired product (entry 3). While
the use of other bases was not beneficial (entries 4 and 5), switching
the solvent to propionitrile increased the yield to 85% (entry 6).
Moreover, we found that the reaction progressed much more
efficiently when it was allowed to slowly warm up, and even under
reduced catalyst loading led to the formation of 4 in 92% isolated
yield (entry 7). Importantly, decreasing the amount of enolate or
arene had little effect on the reaction outcome (entries 8 and 9).
Following the seminal achievements of Lautens, heterobicyclic
alkenes are now widely employed in catalytic ring-opening
reactions. In the case of formal dearomative 1,2-
aminofunctionalizations (Scheme 1A), the observed syn-1,2-
8
selectivity is a result of syn-nucleometalation. We have recently
9
explored an arene-arenophile cycloaddition process that delivers
similar bicyclic structures directly from aromatic precursors
1
0
(
Scheme 1B). In subsequent studies, we have sought to examine
whether the intermediate cycloadducts would directly engage in a
Pd-catalyzed substitution process11 with enolate. Since arene-
12
arenophile adducts have different intrinsic strain as well as
electrophilic
character
compared
to
benzyne-derived
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Table 1. Optimization of Reaction Conditionsa
1.6:1). In general, this process displayed broad functional group
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compatibility and showed a general insensitivity to the electronic
nature of substituents.
Table 2. Ketone and Ester Scope of the Dearomative
a
Carboamination
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aStandard reaction conditions: MTAD (2, 1.0 mmol, 1.0 equiv),
naphthalene (2.0 mmol, 2.0 equiv), solvent (0.13 M), visible light,
–
50 °C, 12 h; then solution of enolate [p-methoxyacetophenone (2.0
mmol, 2.0 equiv), base (1.9 mmol, 1.9 equiv)], solution of catalyst
b
[
2
Pd(dba) (x mol%), dppb (1.2x mol%), THF], 5 h. Determined
1
c
by H NMR integration relative to the internal standard. Isolated
yield after purification by flash chromatography. 1.4 equiv of
d
e
enolate used. 1.5 equiv of naphthalene used.
Having found reaction conditions which resulted in efficient
dearomative difunctionalization of naphthalene, we set out to
investigate the scope of this process using different ketones and
esters (Table 2). Thus, acetophenone (5) and a range of diverse
analogues bearing halogens (6–8), trifluoromethyl (9), and methyl
group (10), gave the corresponding products in high yields.
Moreover, the phenyl motif on the enolate could be substituted with
polynuclear or heteronuclear arenes, as exemplified with
naphthalene (11) and furan (12). Sterically demanding substrates,
represented by different levels of enolate substitution, were
efficiently tolerated (13 and 14), providing product with high
diasteroselectivity (>20:1 for 13, see X-ray). In addition to aryl
ketones, aliphatic ketones could be incorporated (15–17), including
more elaborated substrates encompassing an alkene or protected
hydroxyl group (18 and 19). Cyclic ketones proved to be feasible
substrates as well (20–23), though the diastereoselectivity was
highly dependent on the ring size. At the same time, the
carboamination method could be extended to esters as substrates.
In addition to acetate (24) and derivatives with different
substitution patterns (25–27), protected glycine was also tolerated,
delivering α–amino acid analogue 28. Finally, the robustness and
scalability of this dearomative difunctionalization was tested by
conducting this protocol on a larger scale, and we observe only
slight decrease in yield of product 16. Importantly, in all cases, the
products were obtained as a single diastereoisomer.
aAll reactions were run on 1.0 mmol scale under the standard
conditions. Reported yields are of isolated products and dr was
1
b
determined by H NMR of the crude reaction mixtures. Run at –
c
d
3
0 °C for 12 h. Run on 8.8 mmol scale. Reaction was conducted
e
2 2 2
in CH Cl with LiCl as additive. Pd(dba) /rac-BINAP (5/6 mol%)
used. Relative stereochemistry determined by X-ray.
f
We also examined the feasibility of using benzene as a substrate
for this dearomative process (Table 3, inset). Gratifyingly, by
performing the substitution step at –30 °C, the corresponding syn-
1
,4-carboaminated cyclohexadiene product 39 was obtained in
80% yield. Moreover, using this strategy, benzene also reacted with
other enolates, providing products derived from propiophenone
(
40), an aliphatic ketone (41), and an ester (42) with comparable
efficiency. Unfortunately, the analogous substituted benzene
derivatives react poorly under the current reaction conditions.
This catalytic dearomative difunctionalization is also amenable
1
3
to enantioselective desymmetrization as demonstrated with
naphthalene (Table 4). Thus, two reaction conditions were
14
identified depending upon the nature of the enolate. For example,
a range of ketones under the standard protocol, using (S,S )-tBu-
Phosferrox as a ligand, delivered carboaminated products 4, 13,
6, and 17 in high optical purity (82:18 to 97:3 er). On the other
hand, enantioselective carboamination with esters required
Pd(allyl)Cl] and (R)-DTBM-SEGPHOS as a precatalyst to
achieve good conversion and high selectivities, as exemplified with
6 and 27 (95:5 er).
We next investigated the scope of arenes by using acetophenone
p
3
as an enolate source, as depicted in Table 3. In addition to
1
5
symmetrically 1,4- and 2,3-disubstituted naphthalene derivatives
(29–31), unsymmetrical substrates also function well, though
constitutional isomers were observed resulting from the ring
opening at either site of arene-arenophile cycloadducts. Thus, 1,2-
disubstituted naphthalene-based product 32 was obtained in a 3:1
ratio, and 1-substituted products 33–36 were obtained in 1.4:1 to
1
[
2
2
3
:1 ratio, respectively. Only naphthalene with more remote
substituent at the 2-position resulted in non-selective
difunctionalization (37), and diminished selectivity was also
observed for higher order polyaromatic phenanthrene (38, 46%,
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Table 3. Arene Scope of the Dearomative Carboaminationa
with Pd/C resulted in complete reduction of olefin and urazole,
furnishing ketone 43. Chemoselective hydrogenation of the double
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bond using Rh/alumina or Upjohn dihydroxylation, followed by
1
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urazole oxidation, delivered ketones 44 and 45. Finally,
chemoselective alkene reduction and ketone protection (16→46)
1
8
enabled preparation of amine 47, ketone 48, and α-chloroketone
9.
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aAll reactions were run on 1.0 mmol scale under the standard
conditions. Reported yields are of isolated products, ratio of
Figure 1. Derivatization of product 16. (a) Pd/C (cat.), H
(b) i) Rh/Al (cat.), H , 93%; ii) tBuOCl, AcOH, 79%; (c) i)
OsO4 (cat.), NMO, 87%; ii) NaOCl, 40%; (d) i) Rh/Al (cat.),
, 93%; ii) glycol, TsOH, 85%; (e) i) α-bromoacetophenone,
NaH, 78%; ii) KOH, 97%; (f) NaOCl, 53%; (g) tBuOCl, 77%, 20:1
dr.
2
, 60%;
2
O
3
2
constitutional isomers (in parenthesis) and dr was determined by
2 3
O
1
H NMR of the crude reaction mixtures. bRun on 8.8 mmol scale.
H
2
c
Run with benzene (10 mmol, 10 equiv) under the standard
conditions and at –30 °C for 12 h. dRelative stereochemistry
assigned by analogy.
In conclusion, we have developed a dearomative strategy for 1,4-
carboamination of simple arenes. Our approach features an
arenophile-based cycloaddition followed by Pd-catalyzed
nucleophilic opening of the resulting cycloadducts using ketone- or
ester-derived lithium enolates. The method delivers products with
exclusive syn-1,4-selectivity and high enantioselectivity in the case
of naphthalene. Finally, the products are amenable to further
elaboration, enabling controlled access to a wide range of small,
polyfunctionalized building blocks. Further studies regarding the
expansion of the substrate scope, related transformations, as well
as further applications of the method, are ongoing and will be
reported in due course.
The dearomatized products contain several regions amenable to
further functionalization. As demonstrated with product 16, the
alkene, urazole, and ketone moieties can undergo a series of
selective and orthogonal transformations, enabling rapid
diversification (Figure 1). For example, catalytic hydrogenation
Table 4. Pd-Catalyzed Enantioselective Dearomative
Carboamination of Naphthalenea
ASSOCIATED CONTENT
Supporting Information
This material is available free of charge via the Internet at
http://pubs.acs.org.
Experimental procedures and spectral data for all new
compounds (PDF)
Crystallographic data (CIF)
AUTHOR INFORMATION
Corresponding Author
*sarlah@illinois.edu
Notes
aAll reactions were run on 0.5 mmol scale under the standard
The authors declare no competing financial interests.
conditions. For ketones, (S,S
ligand. For esters, [Pd(allyl)Cl]
p
)-tBu-Phosferrox was used as a
and (R)-DTBM-SEGPHOS were
ACKNOWLEDGMENT
2
used. Reported yields are of isolated products and dr was
Financial support for this work was provided by the University of
Illinois, the National Science Foundation (CAREER Award No.
1
determined by H NMR of the crude reaction mixtures.
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CHE-1654110), and the NIH/National Institute of General Medical
Sciences (R01 GM122891). D. S. is an Alfred P. Sloan Fellow. M.
O. acknowledges the Honjo International Scholarship Foundation.
We also thank Dr. D. Olson and Dr. L. Zhu for NMR spectroscopic
assistance, Dr. D. L. Gray and Dr. T. Woods for X-ray
crystallographic analysis assistance, and F. Sun for mass
spectrometric assistance.
10, 4057. (c) Ogura, T.; Yoshida, K.; Yanagisawa, A.; Imamoto, T. Org.
Lett. 2009, 11, 2245. (d) Nakao, Y.; Kashihara, N.; Kanyiva, K. S.; Hiyama,
T. Angew. Chem., Int. Ed. 2010, 49, 4451. (e) Lautens, M.; Dockendorff, C.
Org. Lett. 2003, 5, 3695. (f) Chen, C.-L.; Martin, S. F. J. Org. Chem. 2006,
71, 4810.
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(7) For recent applications, see: (a) McManus, H. A.; Fleming, M.
J.; Lautens, M. Angew. Chem., Int. Ed. 2007, 46, 433. (b) Fleming, M. J.;
McManus, H. A.; Rudolph, A.; Chan, W. H.; Ruiz, J.; Dockendorff, C.;
Lautens, M. Chem. - Eur. J. 2008, 14, 2112. (c) Lautens, M.; Fagnou, K.;
Zunic, V. Org. Lett. 2002, 4, 3465.
REFERENCES
(
8)Lautens, M.; Hiebert, S.; Renaud, J.-L. J. Am. Chem. Soc. 2001, 123,
834.
9)(a) Hamrock, S. J.; Sheridan, R. S. J. Am. Chem. Soc. 1989, 111, 9247.
(b) Kjell, D. P.; Sheridan, R. S. J. Am. Chem. Soc. 1984, 106, 5368.
10) (a) Southgate, E. H.; Pospech, J.; Fu, J.; Holycross, D. R.; Sarlah, D.
(
1) Arene Chemistry: Reaction Mechanisms and Methods for Aromatic
Compounds, Mortier, J., Ed., John Wiley-VCH, 2016.
2) For selected reviews, see: (a) Colby, D. A.; Bergman, R. G.; Ellman,
6
(
(
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
J. A. Chem. Rev. 2010, 110, 624. (b) Mkhalid, I. A. I.; Barnard, J. H.;
Marder, T. B.; Murphy, J. M.; Hartwig, J. F. Chem. Rev. 2010, 110, 890. (c)
Lyons, T. W.; Sanford, M. S. Chem. Rev. 2010, 110, 1147. (d) Yamaguchi,
J.; Yamaguchi, A. D.; Itami, K. Angew. Chem., Int. Ed. 2012, 51, 8960. (e)
Arockiam, P. B.; Bruneau, C.; Dixneuf, P. H. Chem. Rev. 2012, 112, 5879.
(
Nat. Chem. 2016, 8, 922 (b) Okumura, M.; Nakamata-Huynh, S. M.;
Pospech, J.; Sarlah, D. Angew. Chem., Int. Ed. 2016, 55, 15910.
(11) For reviews on Pd-catalyzed allylic substitution, see: (a) Trost, B.
M.; Van Vranken, D. L. Chem. Rev. 1996, 96, 395. (b) Trost, B. M.;
Crawley, M. L. Chem. Rev. 2003, 103, 2921. (c) Lu, Z.; Ma, S. Angew.
Chem., Int. Ed. 2008, 47, 258. (d) Weaver, J. D.; Recio, A., III; Grenning,
A. J.; Tunge, J. A. Chem. Rev. 2011, 111, 1846.
(12) For recent examples using lithium enolates as nucleophiles, see: (a)
Braun, M., Laicher, F., and Meier, T. Angew. Chem., Int. Ed. 2000, 39,
(3) For recent reviews, see: (a) Roche, S. P.; Porco, J. A. Angew. Chem.,
Int. Ed. 2011, 50, 4068. (b) Pouységu, L.; Deffieux, D.; Quideau, S.
Tetrahedron 2010, 66, 2235. (c) Lewis, S. E. Chem. Commun., 2014, 50,
2
1
821. (d) Pape, A. R.; Kaliappan, K. P.; Kündig, E. P. Chem. Rev. 2000,
00, 2917. (e) See also reference 13.
(4)For selected recent examples, see: (a) Good, S. N.; Sharpe, R. J.;
3
494. (b) Zheng, W.-H.; Zheng, B.-H.; Zhang, Y.; Hou, X.-L. J. Am. Chem.
Johnson, J. S. J. Am. Chem. Soc. 2017, 139, 12422. (b) Wilson, K. B.;
Myers, J. T.; Nedzbala, H. S.; Combee, L. A.; Sabat, M.; Harman, W. D. J.
Am. Chem. Soc. 2017, 139, 11401. (c) Nakayama, H.; Harada, S.; Kono,
M.; Nemoto, T. J. Am. Chem. Soc., 2017, 139, 10188. (d) Zheng, J.; Wang,
S.-B.; Zheng, C.; You, S.-L. J. Am. Chem. Soc. 2015, 137, 4880. (e) García-
Fortanet, J.; Kessler, F.; Buchwald, S. L. J. Am. Chem. Soc. 2009, 131,
Soc. 2007, 129, 7718. (c) Lei, B.-L.; Ding, C.-H.; Yang, X.-F.; Wan, X.-L.;
Hou, X.-L. J. Am. Chem. Soc. 2009, 131, 18250.
(
13) For recent reviews on catalytic asymmetric dearomatizations, see:
Zhuo, C.-X.; Zhang, W.; You, S.-L. Angew. Chem., Int. Ed. 2012, 51,
2662. (b) Zheng, C.; You, S.-L. Chem, 2016, 1, 830.
1
(14) See SI for details.
6
676. (f) Zhuo, C.-X.; You, S.-L. Angew. Chem., Int. Ed. 2013, 52, 10056.
(15) Dai, L.-X.; Tu, T.; You, S.-L.; Deng, W.-P.; Hou, X.-L. Acc. Chem.
(
(
g) Phipps, R. J.; Toste, F. D. J. Am. Chem. Soc. 2013, 135, 1268.
h) Oguma, T.; Katsuki, T. J. Am. Chem. Soc. 2012, 134, 20017.
Res. 2003, 36, 659.
16) (a) Schneider, W. P.; McIntosh, A. V. (Upjohn). U.S. Patent
,769,824, 1956. (b) VanRheenen, V.; Kelly, R. C.; Cha, D. Y. Tetrahedron
Lett. 1976, 17, 1973.
17) For direct oxidation of urazole to ketone, see: (a) Wilson, R. M.;
(
(5) For selected reviews, see: (a) Lautens, M.; Fagnou, K.; Hiebert, S. Acc.
2
Chem. Res. 2003, 36, 48. (b) Rayabarapu, D. K.; Cheng, C.-H. Acc. Chem.
Res. 2007, 40, 971. (c) Woo, S.; Keay, B. A. Synthesis 1996, 6, 669. (d)
Chiu, P.; Lautens, M. Top. Curr. Chem. 1997, 190.
(6)For selected examples, see: (a) Cho, Y.-H.; Zunic, V.; Senboku, H.;
Olsen, M.; Lautens, M. J. Am. Chem. Soc. 2006, 128, 6837. (b) Nishimura,
T.; Tsurumaki, E.; Kawamoto, T.; Guo, X.-X.; Hayashi, T. Org. Lett. 2008,
(
Hengge, A. C. J. Org. Chem. 1990, 55, 197. (b) Wilson, R. M.; Hengge, A.
C.; Ataei, A.; Ho, D. M. J. Am. Chem. Soc. 1991, 113, 7240.
(18) Adam, W.; Pastor, A.; Wirth, T. Org. Lett. 2000, 2, 1295.
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5
5
5
5
5
5
5
5
6
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
ACS Paragon Plus Environment