Palladium-catalyzed chemoselective aminomethylative cyclization and aromatizing allylic amination: Access to functionalized naphthalenes

Article abstract of DOI:10.1021/acs.orglett.0c03365

A palladium-catalyzed chemoselective aminomethylative cyclization and aromatizing allylic amination of enyne-tethered allylic alcohols with aminals is described. Under the reaction conditions, the cationic vinyl allylpalladium species undergoes selective migratory insertion of alkenes rather than reductive elimination with nucleophiles. This strategy provides an efficient and unique approach to the construction of functionalized naphthalenes, which are important building blocks in synthetic organic chemistry. Mechanistic studies have revealed that the selective sequential migratory insertion of enyne and alkene is crucial for the cyclization.

Full text of DOI:10.1021/acs.orglett.0c03365

pubs.acs.org/OrgLett
Letter
Palladium-Catalyzed Chemoselective Aminomethylative Cyclization
and Aromatizing Allylic Amination: Access to Functionalized
Naphthalenes
Bangkui Yu, Houjian Yu, and Hanmin Huang*
Cite This: https://dx.doi.org/10.1021/acs.orglett.0c03365
Read Online
sı
*
Metrics & More
Article Recommendations
Supporting Information
ACCESS
ABSTRACT: A palladium-catalyzed chemoselective aminomethy-
lative cyclization and aromatizing allylic amination of enyne-
tethered allylic alcohols with aminals is described. Under the
reaction conditions, the cationic vinyl allylpalladium species
undergoes selective migratory insertion of alkenes rather than
reductive elimination with nucleophiles. This strategy provides an
efficient and unique approach to the construction of functionalized
naphthalenes, which are important building blocks in synthetic
organic chemistry. Mechanistic studies have revealed that the
selective sequential migratory insertion of enyne and alkene is
crucial for the cyclization.
alladium-catalyzed allylic substitution reactions (ASRs)
pioneered by Tsuji and Trost have been widely applied in
present in such an allylpalladium intermediate, the correspond-
ing cyclization reaction would become intricate as it is hard to
control the active allylmetal species to be selectively
intercepted by the alkenes through migratory insertion
(Scheme 1b). Herein, we describe an approach for facilitating
the palladium capture of the alkene and enabling the
allylpalladium species to be selectively intercepted by alkenes
via enhancing the electrophilicity of the palladium center of the
allylpalladium species.
We envisioned that tuning the electronic nature of the metal
center of the allylpalladium species could facilitate it to
undergo alkene insertion. Previous pioneering studies have
established that the insertion of alkene into the M−C bonds of
metal complexes containing more electrophilic metal centers is
faster than those into M−C bonds of complexes containing
more electron-rich metal centers.5 In this context, it would be
expected that the migratory insertion of alkene incurred by the
π-allylpalladium could be facilitated by the electron-deficient
allylic ligands. Recently, our research group has established a
highly chemo- and regioselective 1,4-aminomethylamination of
1,3-enynes with aminals to afford allenic 1,5-diamines,6 in
which the cationic vinyl π-allylpalladium species was generated
as a key intermediate.7 The vinyl allylic ligand possessing
stronger electron acceptability than alkyl ones could render the
P
organic chemistry.1 Many classes of carbon-centered nucleo-
philes and heteroatom-centered nucleophiles can be employed
to intercept the key allylpalladium intermediates via reductive
elimination.2 Oppolzer has discovered that the allylpalladium
species could also be intercepted by adjoining olefins through
migratory insertion (Scheme 1a).3 Such a transformation has
found widespread use in constructing five- or six-membered
carbocycles and heterocycles.4 However, when both active
heteroatom-centered nucleophiles and olefin moieties are
Scheme 1. Cyclization of Allylpalladium Species with
Adjoining Alkenes or a Nucleophile
Received: October 8, 2020
https://dx.doi.org/10.1021/acs.orglett.0c03365
© XXXX American Chemical Society
Org. Lett. XXXX, XXX, XXX−XXX
A

Organic Letters
pubs.acs.org/OrgLett
Letter
a
coordinated palladium center more electrophilic to capture the
alkene to undergo migratory insertion with the corresponding
allylpalladium species.
Table 1. Optimization of the Reaction Conditions
Fascinated and inspired by this unique feature, we
envisioned that cationic vinyl π-allylpalladium species B
generated from enyne-tethered allylic alcohols 1 via migratory
insertion of enyne into the C−Pd bond of cationic palladium
complex A should favor the alkene insertion to exclusively
furnish the metallo-ene reaction (Scheme 1c).
To test the viability of the cascade reaction, substrate 1a was
subjected to 5 mol % Pd(Xantphos)(CH3CN)2OTf2 and
aminal 2a at 80 °C in THF (Scheme 2). Gratifyingly, the
yield
b
entry
catalyst
Pd(CH3CN)2Cl2
additive
solvent
(%)
1
2
3
4
5
6
7
8
AgOTf
AgOTf
AgOTf
AgOTf
AgOTf
AgOTf
−
DCM
THF
TBME
dioxane
CH3CN
THF
57
81
40
57
60
76
trace
0
Pd(CH3CN)2Cl2
Pd(CH3CN)2Cl2
Pd(CH3CN)2Cl2
Pd(CH3CN)2Cl2
[Pd(allyl)Cl]2
Pd(OAc)2
Scheme 2. Initial Result for the Aminomethylative
Cyclization via Sequential Alkyne and Alkene Insertion
THF
THF
Pd2(dba)3
−
9
10
11
Pd2(dba)3
Pd2(dba)3
Pd(Xantphos)
(CH3CN)2(OTf)2
Pd(Xantphos)
(CH3CN)2(OTf)2
Pd(Xantphos)
(CH3CN)2(OTf)2
AgOTf
HOTf
−
THF
THF
THF
68
62
83
c
12
−
−
THF
THF
58
82
d
13
corresponding cyclization product was formed in 76% yield
along with 4aa, which might be generated from 3aa via C−O
bond cleavage and aromatization. The O-trapping product
arising from reductive elimination with -OH was not detected.
Inspired by this initial result, we envisioned that if benzene-
tethered enyne-allylic alcohol were subjected to the reaction
condition, the subsequent dehydration−aromatization reaction
would be favored to give the corresponding functionalized
naphthalenes.8
a
Reaction conditions: 1b (0.3 mmol), 2a (0.36 mmol), Pd (5 mol %),
Ag (10 mol %), Xantphos (6 mol %), solvent (1.0 mL), 80 °C, 12 h.
b
c
d
Isolated yield. At 60 °C. 1b (0.36 mmol), 2a (0.30 mmol).
First, the substrate scope with respect to the enyne-tethered
allylic alcohols was examined, and the results are summarized
in Scheme 3. A series of enyne-tethered allylic alcohols bearing
To verify the feasibility of the proposed cascade reaction, we
began our investigation with the reaction between 1-[2-(but-3-
en-1-yn-1-yl)phenyl]prop-2-en-1-ol (1b) and N,N,N′,N′-tetra-
benzylmethanediamine (2a) in CH2Cl2 at 80 °C with
Pd(CH3CN)2Cl2 as a catalyst precursor and AgOTf as an
additive. To our surprise, an unexpected functionalized
naphthalene 4ba with two amine moieties was obtained in
57% yield when Xantphos served as the ligand (Table 1, entry
1). Product 4ba could be viewed as incorporating one
molecule of aminal into the naphthalene skeleton. Inspired
by this promising result, we next sought to improve the
efficiency of the cascade cyclization and substituted reaction.
Screening of the solvent demonstrated that the corresponding
naphthalene product 4ba could be obtained in 81% yield with
THF as the solvent (Table 1, entries 1−5). Subsequently,
several other palladium catalyst precursors were examined, and
it was found that almost no desired product was observed with
Pd(OAc)2 or Pd2(dba)3 as the palladium source (Table 1,
entries 6−8). However, the reaction performed well in the
presence of a catalytic amount of AgOTf or HOTf with
Pd2(dba)3 as the palladium source (Table 1, entries 9 and 10),
indicating the importance of TfO− as a counteranion for
cationic palladium species and that the Pd(0) was involved in
the reaction presented here. As expected, almost the same yield
(83%) of 4ba was gained when cationic palladium Pd-
(Xantphos)(CH3CN)2(OTf)2 was utilized as the catalyst
(Table 1, entry 11). In addition, the decrease in reaction
temperature has diminished the reactivity (Table 1, entry 12).
The yield of 4ba was not improved further by slightly adjusting
the ratio of starting materials (Table 1, entry 13).
Scheme 3. Substrate Scope of Enyne-Tethered Allylic
Alcohols
a
a
Reaction conditions: 1 (0.3 mmol), 2a (0.36 mmol), Pd(Xantphos)-
With the optimal reaction conditions in hand, the generality
of this palladium-catalyzed cascade process was investigated.
(CH3CN)2(OTf)2 (5 mol %), THF (1.0 mL), 80 °C, 12 h. Isolated
yield.
B
https://dx.doi.org/10.1021/acs.orglett.0c03365
Org. Lett. XXXX, XXX, XXX−XXX

Organic Letters
pubs.acs.org/OrgLett
Letter
different substituents in the phenyl ring reacted smoothly with
aminal 2a, leading to the corresponding products in moderate
to good yields (4ba−4ma). There is no essential correlation
between reactivity and the electronic properties of substituents
on the phenyl ring, as both electron-donating substituents
(CH3, TBSO, and OCH3) and electron-withdrawing groups
(F, Cl, and CF3) gave their corresponding naphthalene
derivatives in good yields. Moreover, for substrates with
disubstituents on the aryl ring, including the dimethoxy and
methylenedioxy-substituted enyne-tethered allylic alcohols, the
reactions proceeded well to deliver the desired products 4fa
and 4ga, respectively, in good yields. Notably, similar results
were obtained regardless of the substitution pattern of the
substituents on the aryl ring (4ha−4ja). In addition, the
thiophene-containing substrate was also compatible with this
reaction, generating the corresponding thianaphthene 4na in
76% yield. To our delight, the reaction could be extended to
enyne-tethered allylic alcohols with methyl and trifluoromethyl
functional groups attached at the β position of the alkene
moiety, producing the desired products in moderate to good
yields (4oa and 4pa). The enyne-tethered allylic alcohols with
substituents at the alkene terminus were also tolerated in this
reaction system to afford the corresponding products in good
yields (4qa and 4ra). In addition, the benzyl-deuterated
naphthalene derivative could be obtained with good yield and
high selectivity from deuterated aminal under standard
reaction conditions (4ba-d2).
morpholine, could give the corresponding functionalized
naphthalene 4bl in decent yield.
The synthetic versatility of this catalytic protocol was
demonstrated through large-scale reaction and functional
group transformations of the resulting naphthalene derivatives
(Scheme 4). When the model reaction of enyne-tethered allylic
Scheme 4. Transformations of Product 4ba
alcohols 1b and aminal 2a was performed on a 10 mmol scale
in the presence of 5 mol % catalyst, the corresponding product
4ba was obtained in 85% yield (4.88 g). The C−N bond in
compound 4ba could be selectively cleaved with
ClCO2CHClCH3 to form chlorinated product 5 [the structure
1
of product 5 was determined by the comparison of the H
NMR spectra of products 4ba, 4ba-d2, and 5 (for details, see
the Supporting Information)].9 Further nucleophilic attack by
p-toluenethiol afforded the corresponding thioether 6 in 92%
yield.10 In addition, alkoxylated products 7 and 8 could also be
obtained via a one-pot, two-step cascade reaction without
separation of benzyl chloride 5.
Next, we explored the scope of aminals for the synthesis of
functionalized naphthalene derivatives. As shown in Table 2, a
a
Table 2. Substrate Scope of Aminals
To gain insights into the possible mechanism of this process,
several control experiments were conducted (Scheme 5). First,
Scheme 5. Control Experiments
entry
R
4
yield (%)
1
2
3
4
5
6
7
8
C6H5CH2-
4ba
4bb
4bc
4bd
4be
4bf
4bg
4bh
4bi
83
73
70
73
77
65
79
77
41
66
74
60
4-MeC6H4CH2-
4-t-Bu-C6H4CH2-
4-FC6H4CH2-
2-FC6H4CH2-
3-FC6H4CH2-
4-ClC6H4CH2-
2-ClC6H4CH2-
4-BrC6H4CH2-
9
10
11
12
4-CF3C6H4CH2-
(S)-N-benzyl-N-1-phenylethyl
-CH2CH2OCH2CH2-
4bj
4bk
4bl
a
Reaction conditions: 1b (0.3 mmol), 2 (0.36 mmol), Pd(Xantphos)-
(CH3CN)2(OTf)2 (5 mol %), THF (1.0 mL), 80 °C, 12 h. Isolated
yield.
variety of aminals derived from dibenzylamines containing
different substituents performed well to give the corresponding
products in moderate to good yields (4ba−4bj). Either
electron-donating (CH3 and t-Bu) or electron-withdrawing
(F, Cl, Br, and CF3) groups on the phenyl moiety of aminals
were tolerated well. Meanwhile, aminal derived from a chiral
benzylamine gave the corresponding product (4bk) in 74%
yield. Moreover, aminal prepared from alicyclic amines, such as
C
https://dx.doi.org/10.1021/acs.orglett.0c03365
Org. Lett. XXXX, XXX, XXX−XXX

Organic Letters
pubs.acs.org/OrgLett
Letter
the catalytic reaction with Pd(Xantphos)(CH2NBn2)OTf
(complex A)11 as a catalyst was conducted, and the desired
product 4ba could be exclusively obtained in 70% yield, which
indicated that complex A was most likely involved in this
reaction. HRMS analysis of the reaction mixture showed a peak
at m/z 1078.3074, which corresponded to the mass of [B −
OTf]+ or [C − OTf]+. Another peak at m/z 1060.3062 was
also detected, which was assigned to the mass of [E − OTf]+.
Intermediate D was also observed as the peak at m/z
1078.3074 was detected. These results supported that tentative
intermediates B (or C), D, and E might be involved in the
catalytic cycle of this transformation. Moreover, the stoichio-
metric reaction of 1b and complex A was also conducted under
the standard reaction conditions. Although no product 4ba was
observed, the HRMS analysis demonstrated that tentative
intermediates B or C and E were also produced. In addition, to
rule out the possibility that the reaction is initiated by the
oxidative addition of allyl alcohol 1b with Pd(0) to form
intermediate II, the catalytic reaction and stoichiometric
reaction with intermediate II and palladium complex A were
carried out and we found that no desired product was detected.
The results presented above excluded the possibility that the
reaction goes through intermediate II (for details, see the
Supporting Information).
In summary, we have disclosed a strategy to facilitate π-
allylpalladium species to be exclusively intercepted by alkene
via enhancing the electrophilicity of the metal center, which
realized the first metallo-ene-type cyclization with an O-
centered nucleophile containing allylpalladium species. This
method has enabled a palladium-catalyzed chemoselective
aminomethylative cyclization and aromatizing allylic amination
of enyne-tethered allylic alcohols with aminals via C−N and
C−O bond activation. A wide range of functionalized
naphthalenes have been obtained in good yields, which
provides a versatile platform for the design of drugs and
functional materials. Further investigation will be focused on
the application of this strategy to many other palladium-
catalyzed aminomethylation-aromatizing cyclization reactions.
ASSOCIATED CONTENT
* Supporting Information
■
sı
The Supporting Information is available free of charge at
https://pubs.acs.org/doi/10.1021/acs.orglett.0c03365.
Experimental procedures and characterization data
(PDF)
Accession Codes
CCDC 2032165 contains the supplementary crystallographic
data for this paper. These data can be obtained free of charge
via www.ccdc.cam.ac.uk/data_request/cif, or by emailing
data_request@ccdc.cam.ac.uk, or by contacting The Cam-
bridge Crystallographic Data Centre, 12 Union Road,
Cambridge CB2 1EZ, UK; fax: +44 1223 336033.
On the basis of the results presented above and our previous
work,12 a plausible reaction mechanism was proposed (Figure
1). The reaction was initiated by the formation of cyclo-
AUTHOR INFORMATION
Corresponding Author
■
Hanmin Huang − Hefei National Laboratory for Physical
Sciences at the Microscale and Department of Chemistry,
University of Science and Technology of China, Hefei 230026,
P. R. China; Center for Excellence in Molecular Synthesis of
CAS, Hefei 230026, P. R. China; orcid.org/0000-0002-
0108-6542; Email: hanmin@ustc.edu.cn
Authors
Bangkui Yu − Hefei National Laboratory for Physical Sciences at
the Microscale and Department of Chemistry, University of
Science and Technology of China, Hefei 230026, P. R. China
Houjian Yu − Hefei National Laboratory for Physical Sciences at
the Microscale and Department of Chemistry, University of
Science and Technology of China, Hefei 230026, P. R. China
Figure 1. Proposed catalytic cycle.
Complete contact information is available at:
https://pubs.acs.org/10.1021/acs.orglett.0c03365
palladated complex A. First, the triple bond of enyne-tethered
allylic alcohols 1a coordinates to the palladium center and then
forms allylpalladium complex B by migratory insertion of the
triple bond into the C−Pd bond of complex A. Subsequently,
intramolecular migratory insertion of the double bond takes
place to give alkylpalladium complex C, which is followed by β-
hydride elimination to deliver intermediate D as well as
HPdOTf. Reductive elimination of the palladium hydride
species gives Pd(0), which undergoes oxidative addition with
intermediate D to afford π-allylpalladium complex E aided by
HOTf. Intermediate E is then intercepted by an aminal to form
intermediate F via reductive elimination. Finally, the oxidative
addition of intermediate F to Pd(0) delivers the desired
product 4ba together with regenerating active palladium
complex A for the next catalytic cycle.
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
This research was supported by the National Natural Science
Foundation of China (21672199, 21790333, 21925111, and
21702197).
REFERENCES
■
(1) For selected reviews of the Tsuji−Trost reaction, see: (a) Trost,
B. M.; Van Vranken, D. L. Chem. Rev. 1996, 96, 395−422. (b) Trost,
B. M.; Crawley, M. L. Chem. Rev. 2003, 103, 2921−2943. (c) Trost,
B. M.; Machacek, M. R.; Aponick, A. Acc. Chem. Res. 2006, 39, 747−
D
https://dx.doi.org/10.1021/acs.orglett.0c03365
Org. Lett. XXXX, XXX, XXX−XXX

Organic Letters
pubs.acs.org/OrgLett
Letter
760. (d) Lu, Z.; Ma, S. Angew. Chem., Int. Ed. 2008, 47, 258−297.
(e) Sundararaju, B.; Achard, M.; Bruneau, C. Chem. Soc. Rev. 2012,
41, 4467−4483. (f) Haydl, A. M.; Breit, B.; Liang, T.; Krische, M. J.
Angew. Chem., Int. Ed. 2017, 56, 11312−11325. (g) Noreen, S.; Fawad
Zahoor, A.; Ahmad, S.; Shahzadi, I.; Irfan, A.; Faiz, S. Curr. Org. Chem.
2019, 23, 1168−1213.
(g) Jiang, W.; Li, Y.; Wang, Z.-H. Acc. Chem. Res. 2014, 47, 3135−
3147. (h) Guo, Y.-R.; Cao, Q.-D.; Hong, Z.-S.; Tan, Y.-Y.; Chen, S.-
D.; Jin, H.-J.; Tan, K.-S.; Wang, D.-Y.; Yan, Y. Military Med. Res. 2020,
7, 11.
(9) Olofson, R. A.; Martz, J. T.; Senet, J.-P.; Piteau, M.; Malfroot, T.
J. Org. Chem. 1984, 49, 2081−2082.
(10) Yu, M.; Xie, Y.; Xie, C.; Zhang, Y. Org. Lett. 2012, 14, 2164−
(2) For selected examples of allylic substitution reactions, see:
(a) Jellerichs, B. G.; Kong, J.-R.; Krische, M. J. J. Am. Chem. Soc. 2003,
125, 7758−7759. (b) Kinoshita, H.; Shinokubo, H.; Oshima, K. Org.
Lett. 2004, 6, 4085−4088. (c) Nemoto, T.; Matsumoto, T.; Masuda,
T.; Hitomi, T.; Hatano, K.; Hamada, Y. J. Am. Chem. Soc. 2004, 126,
3690−3691. (d) Mohr, J. T.; Behenna, D. C.; Harned, A. M.; Stoltz,
B. M. Angew. Chem., Int. Ed. 2005, 44, 6924−6927. (e) Ibrahem, I.;
2167.
(11) Xie, Y.; Hu, J.; Wang, Y.; Xia, C.; Huang, H. J. Am. Chem. Soc.
2012, 134, 20613−20616.
(12) (a) Hu, J.; Xie, Y.; Huang, H. Angew. Chem., Int. Ed. 2014, 53,
7272−7276. (b) Qin, G.; Li, L.; Li, J.; Huang, H. J. Am. Chem. Soc.
2015, 137, 12490−12493. (c) Liu, Y.; Xie, Y.; Wang, H.; Huang, H. J.
Am. Chem. Soc. 2016, 138, 4314−4317. (d) Li, L.; Liu, P.; Su, Y.;
Huang, H. Org. Lett. 2016, 18, 5736−5739. (e) Li, L.; Zhou, X.; Yu,
B.; Huang, H. Org. Lett. 2017, 19, 4600−4603. (f) Qi, X.; Liu, S.; Lan,
Y. Organometallics 2016, 35, 1582−1585. (g) Qiao, C.; Chen, A.; Gao,
B.; Liu, Y.; Huang, H. Chin. J. Chem. 2018, 36, 929−933.
́
Cordova, A. Angew. Chem., Int. Ed. 2006, 45, 1952−1956. (f) Bravo-
Altamirano, K.; Montchamp, J.-L. Org. Lett. 2006, 8, 4169−4171.
(g) Behenna, D. C.; Liu, Y.; Yurino, T.; Kim, J.; White, D. E.; Virgil, S.
C.; Stoltz, B. M. Nat. Chem. 2012, 4, 130−133. (h) Li, Y.-X.; Xuan,
Q.-Q.; Liu, L.; Wang, D.; Chen, Y.-J.; Li, C.-J. J. Am. Chem. Soc. 2013,
135, 12536−12539.
(3) For selected reviews of the metallo-ene reaction, see:
(a) Oppolzer, W. In Comprehensive Organic Synthesis; Trost, B. M.,
Fleming, I., Eds.; Pergamon: Oxford, U.K., 1991; Vol. 5, Chapter 1.2.
(b) Oppolzer, W. In Comprehensive Organometallic Chemistry II; Abel,
E. W., Stone, F. G. A., Wilkinson, G., Eds.; Pergamon: Oxford, U.K.,
1995; Vol. 12, Chapter 8.3. (c) Oppolzer, W. Angew. Chem., Int. Ed.
Engl. 1989, 28, 38−52. (d) Oppolzer, W. Pure Appl. Chem. 1990, 62,
1941−1948. (e) Heumann, A.; Reglier, M. Tetrahedron 1995, 51,
975−1015. (f) Yadav, S.; Ramasastry, S. S. V. Chem. - Asian J. 2020,
15, 2764−2774.
(4) For selected examples of metallo-ene reaction, see: (a) Oppolzer,
W.; Pitteloud, R.; Strauss, H. F. J. Am. Chem. Soc. 1982, 104, 6476−
6477. (b) Trost, B. M.; Lautens, M. J. Am. Chem. Soc. 1985, 107,
1781−1783. (c) Gomez-Bengoa, E.; Cuerva, J. M.; Echavarren, A. M.;
Martorell, G. Angew. Chem., Int. Ed. Engl. 1997, 36, 767−769.
(d) Tsukada, N.; Sugawara, S.; Inoue, Y. Org. Lett. 2000, 2, 655−657.
(e) Michelet, V.; Galland, J.-C.; Charruault, L.; Savignac, M.; Genet,
J.-P. Org. Lett. 2001, 3, 2065−2067. (f) Campana, A. G.; Bazdi, B.;
Fuentes, N.; Robles, R.; Cuerva, J. M.; Oltra, J. E.; Porcel, S.;
Echavarren, A. M. Angew. Chem., Int. Ed. 2008, 47, 7515−7519.
(g) Liang, H.; Yan, F.; Dong, X.; Liu, Q.; Wei, X.; Liu, S.; Dong, Y.;
Liu, H. Chem. Commun. 2017, 53, 3138−3141. (h) Bankar, S. K.;
Singh, B.; Tung, P.; Ramasastry, S. S. V. Angew. Chem., Int. Ed. 2018,
57, 1678−1682. (i) Yadav, S.; Hazra, R.; Singh, A.; Ramasastry, S. S.
V. Org. Lett. 2019, 21, 2983−2987. (j) Singh, B.; Bankar, S. K.;
Kumar, K.; Ramasastry, S. S. V. Chem. Sci. 2020, 11, 4948−4953.
(5) For a leading review of migratory insertion, see: (a) Cavell, K. J.
Coord. Chem. Rev. 1996, 155, 209−243. For selective reports of
migratory insertion, see: (b) Mecking, S.; Johnson, L. K.; Wang, L.;
Brookhart, M. J. Am. Chem. Soc. 1998, 120, 888−899. (c) Tye, J. W.;
Hartwig, J. F. J. Am. Chem. Soc. 2009, 131, 14703−14712. (d) Hanley,
P. S.; Hartwig, J. F. J. Am. Chem. Soc. 2011, 133, 15661−15673.
(e) Xie, Y.; Hu, J.; Xie, P.; Qian, B.; Huang, H. J. Am. Chem. Soc.
2013, 135, 18327−18330.
(6) Zhang, Y.; Yu, B.; Gao, B.; Zhang, T.; Huang, H. Org. Lett. 2019,
21, 535−539.
(7) (a) Nishimura, T.; Makino, H.; Nagaosa, M.; Hayashi, T. J. Am.
Chem. Soc. 2010, 132, 12865−12867. (b) Wang, M.; Liu, Z.-L.;
Zhang, X.; Tian, P.-P.; Xu, Y.-H.; Loh, T.-P. J. Am. Chem. Soc. 2015,
137, 14830−14833.
(8) (a) Bringmann, G.; Ochse, M.; Schupp, O.; Tasler, S. In Progress
in the Chemistry of Organic Natural Products; Herz, W., Falk, H., Kirby,
G. W., Moore, R. E., Tamm, C., Eds.; Springer: New York, 2001; Vol.
̈
̈
82, p 1. (b) Watson, M. D.; Fechtenkotter, A.; Mullen, K. Chem. Rev.
2001, 101, 1267−1300. (c) Dai, J.; Liu, Y.; Zhou, Y.-D.; Nagle, D. G.
J. Nat. Prod. 2007, 70, 1824−1826. (d) Reddy, R. A.; Baumeister, U.;
Keith, C.; Tschierske, C. J. Mater. Chem. 2007, 17, 62−75.
(e) Anthony, J. E. Angew. Chem., Int. Ed. 2008, 47, 452−483.
(f) Shibasaki, M.; Matsunaga, S. BINOL. In Privileged Chiral Ligands
and Catalysts; Zhou, Q.-L., Ed.; Wiley: New York, 2011; pp 295−332.
E
https://dx.doi.org/10.1021/acs.orglett.0c03365
Org. Lett. XXXX, XXX, XXX−XXX