Intermolecular oxidative amination of unactivated alkenes by dual photoredox and copper catalysis

Article abstract of DOI:10.1039/d0sc05952h

Oxidative amination of alkenesviaamidyl radical addition is potentially an efficient method to generate allylic amines, which are versatile synthetic intermediates to bioactive compounds and organic materials. Here by combining photochemical generation of

Full text of DOI:10.1039/d0sc05952h

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DOI: 10.1039/D0SC05952H
ARTICLE
Intermolecular oxidative amination of unactivated alkenes by
dual photoredox and copper catalysis
Xiangli Yi and Xile Hu*
Received 00th January 20xx,
Accepted 00th January 20xx
Abstract: Oxidative amination of alkenes via amidyl radical addition is potentially an efficient method to generate allylic
amines, which are versatile synthetic intermediates to bioactive compounds and organic materials. Here by combining
photochemical generation of amidyl radicals with Cu-mediated β-H elimination of alkyl radicals, we have developed an
intermolecular oxidative amination of unactivated alkenes. The reaction relies on tandem photoredox and copper catalysis,
and works for both terminal and internal alkenes. The radical nature of the reaction and the mild conditions lead to high
functional group tolerance.
DOI: 10.1039/x0xx00000x
Oxidative amination of alkenes1 is a versatile method to rarely applied for the synthesis of allylic amines. During the
synthesize allylic amines and related nitrogen-containing prepration of this manuscript, the group of Ritter reported an
compounds, which are prevalent in bioactive molecules and elegant method for allylic amination through addition of
organic materials.2 Pd-catalyzed allylic C-H activation is an aminium radicals generated from energy transfer between a
efficient approach to synthesize allylic amines (Scheme 1a), yet photocatalyst and iminothianthrenes under illumination to
so far only mono-substituted terminal alkenes are suitable alkenes.12 Radical−radical cross-coupling between the resulting
substrates.3 Anti-Makovnikov oxidative amination via carbon radical and persistent thianthrenium radical followed by
aminopalladation4 is another potentially versatile method elimination, or oxidation of the carbon radical by thianthrenium
(Scheme 1a), but at this stage chain-walking is a problem for radical followed by deprotonation furnishes the products. Here
many substrates. Allylic amines can also be prepared by allylic we report an alternative approach based on synergetic
C−H insertion of metal−nitrenoid of alkenes typically with a photoredox and Cu catalysis.
branch selectivity (Scheme 1b).5 These methods have generally
Cu has been reported to mediate -H elimination of alkyl
limited tolerance for substrates containing highly polar or radicals to produce alkenes.13 Recent reports described facile
nucleophilic moieties. Addition of amidyl radical, typically generation of an amidyl radical via reduction of a hydroxylamine
stabilized by an electron-withdrawing group, to an alkene precursor by an excited state of a photoredox catalyst.14,7f In
followed by elimination of β-H provides an alternative strategy this context, we envisioned synergetic photoredox and Cu
to effect the oxidative amination (Scheme 1c). This strategy has cataylsis for oxidative amination of unactivated alkenes
intrinsic anti-Makovnikov selectivity, is potentially suitable for (Scheme 1d). The photochemically generated amidyl radical
internal alkenes and the radical nature of the reaction is adds to an alkene to give an alkyl radical, which is trapped by a
compatible with polar substrates, which are important for Cu species. The latter undergoes -H elimination to give the
industrial applications.6
desired allylic amine and a reduced Cu species, which can be
Amidyl radical addition to alkenes for intramolecular oxidized back to the intial Cu catalyst by the oxidized
cyclization7 and the intermolecular addition to activated photocatalyst. Here we descibe the successful development of
alkenes8 have been well explored. Unactivated alkenes are such a process.
more challenging substrates for intermolecular amidyl radical Studer and co-workers showed that oxidation of -amido-oxy
addition because the carbon radical formed upon addition are acids by a photoexcited catalyst gave a carboxyl radical, which
not stabilized by a heteroatom or aryl group as in the case of transfomred into an amidyl radical after CO2 and
activated alkenes. The high reactivity of these radical aldehyde/ketone fragmentation.9a,10b,10e They also showed that
intermediates makes selective further funtionalization harder. these electrophilic amidyl radicals could add to unactivated
Elegant approaches have been developed to trap such C- alkenes
for
eventual
amidofluorination
and
radicals by a hydrogen donor9 or a SOMOphile10 or a Cu(II)-CF3 carboamindation.9a,10b,10e Inspired by these studies we explored
species11 for further functionalization. However, oxidative various N-(benzoyloxy)carbamates as sources of amidyl radicals
amination of unactivated alkenes via amidyl radical addition is under photoredox conditions (Scheme S1). We found that 1,
with a Troc-protection (Troc = 2,2,2-Trichloroethoxycarbonyl),
could react with alkene 2a to afford the allylic amine derivative
3a in 38% yield (Table 1, Entry 1), when 1% of Ir(ppy)3 (ppy = 2-
Laboratory of Inorganic Synthesis and Catalysis, Institute of Chemical Sciences and
(2-pyridinyl)phenyl) was used as a photocatalyst and 15% of
Cu(2-ethylhexanoate)2 was used as a metal catalyst. Troc-NH2
was the main side product and diamination was not observed.
The reaction conditions were then optimized (Table S1-4,
Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015,
Switzerland. E-mail: xile.hu@epfl.ch
† Electronic Supplementary Information (ESI) available: [details of any
supplementary information available should be included here]. See
DOI: 10.1039/x0xx00000x
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ARTICLE
Journal Name
Entry
1
Variations
Cu(2-Ethyl hexanoate)2
instead of Cu(OPiv)2
Additives
Yieldb/ %
Supporting Information). A summary is provided in Table 1. The
use of Cu(OPiv)2 as metal catalyst improved the yield to 42%
(Entry 2), while Cu(OTf)2 was not able to catalyze the reaction
(Entry 3). Addition of 1 equiv. of Zn(OPiv)2 (Entry 4) or Mg(OPiv)2
(Entry 5) decreased the yield, yet 1 equiv. of Mg(OPiv)2 and H2O
slightly increased the yield to 44% (Entry 6). Notably, the
addition of H2O resulted in a precipitate during the reaction,
which was analyzed as mainly Mg(4-cyanobenzoate)2*xH2O.
The replacement of Ir(ppy)3 by Ir (dfppy)2(ppy) (dfppy = 2-(2-
pyridinyl)-3,5-difluorophenyl) further increased the yield to
49% (Entry 7). Increasing the amount of alkene to 2 equiv. and
3 equiv. increased the yield to 59% and 64%, respectively
(Entries 8 and 9). A slow generation of the amidyl radical by slow
addition of 1 to the reaction mixture improved further the yield
View Article Online
DOI: 10.1039/D0SC05952H
-
38
2
3
-
-
-
42
0
Cu(OTf)2 instead of
Cu(OPiv)2
4
5
6
-
-
-
1 eq. Zn(OPiv)2
1 eq. Mg(OPiv)2
1 eq. Mg(OPiv)2 + 1
eq. H2O
1 eq. Mg(OPiv)2 + 1
eq. H2O
1 eq. Mg(OPiv)2 + 1
eq. H2O
1 eq. Mg(OPiv)2 + 1
eq. H2O
21
38
44
7
8
Ir(dfppy)2(ppy) instead
of Ir(ppy)3
49
59
Ir(dfppy)2(ppy) instead
of Ir(ppy)3, 2 eq. 2a
Ir(dfppy)2(ppy) instead
of Ir(ppy)3, 3 eq. 2a
Ir(dfppy)2(ppy) instead
of Ir(ppy)3, 3 eq. 2a, 10%
Cu(OPiv)2,
9
64
of 3a to 77% (70% after isolation, Entry 10).
10c
1 eq. Mg(OPiv)2 + 1
eq. H2O
77 (70d)
a) Pd catalyzed oxidative amination
HNR1R2
R2
N
R
R
R1
R
R
via
or
a
Pd
Conditions: All reagents of indicated amount dissolved in 1 mL CH3CN in a glass
vial (d = 2 cm), blue LED radiation for 24 h. NMR yield with mesitylene as an
internal standard. Slow addition procedure: 0.02 mmol 1 and all other reagents
were dissolved in 0.2 mL CH3CN; the rest of 1 (0.08 mmol) was dissolved in 0.4 mL
Pd
(ref. 4)
b
(ref. 3)
b) Oxidative amination via metal nitrenoid
R1
c
R
M
N
R
(ref. 5)
d
NHR1
CH3CN; the latter was added at 1.2 uL/min to the former after reaction starts.
H
Isolated yield.
c) Oxidative amination via amidyl radical addition
O
R2
N
R2
R1
R
O
R2
Based on the optimal conditions, we examined the scope of
terminal alkenes (Figure 1). Remote electrophilic functionalities
such as bromide (2b), iodide (2c), and terminal epoxide (2d)
were all tolerated to afford the products in good yields (3b-3d,
66-75%). Alcohol (2e) and amide (2f) were also compatible. A
range of alkenes containing a terminal carboxylic acid group
were tested. 9-Decenoic acid (2g), 5-hexenoic acid (2h) and 4-
pentenoic acid (2i), but not 3-butenoic acid, were successfully
aminated. The products were isolated after methylation as
methyl esters in moderate yields (50-53%). Polar substrates (2j,
2k), derived from L-phenylalanine and L-threonine,
respectively, were also viable for this reaction. When a more
electron-deficient alkenyl group was present in the internal
position (2l, 2m), amination of the terminal alkenyl group was
dominant, consistent with electrophilic nature of the amidyl
radical.14a
N
R
- H
O
N
R
R1
R1
H
H
Intrinsic anti-Makovnikov selectivity
Terminal& Internal alkenes
Tolerance for polar substrates
R2 might be -OtBu, -OCH2CCl3, etc
d) Reaction design: intermolecular oxidative amination of unactivated alkenes via
tandem photoredox and Cu catalysis
H
R
H
N
CuII
O
N
N
R
SET
PC
PC*
SET
hv
N
R
CuI
PC
Scheme 1. Different approaches to oxidative amination of alkenes (a, b and c) and
reaction design of this work (d).
Next, alkenes with various substitutions at the C3 position
were examined. A bulky substituent, such as cyclohexyl (2n),
tert-butyl (2o) and 1-hydroxycyclohexyl (2p), didn't deteriorate
the reaction yield. However, double substitutions at C3
decreased the yield (3q, 23%). In the case of a phenyl
substitution (2r), 3r was obtained in 40% yield, with the cis-
alkene as the major isomer.15 Although 3-butenoic acid was not
a suitable substrate, the esters of 3-butenoic acid could be used
for the generation of α,β- unsaturated esters (3s-3v). 4-hydroxyl
(2u) and 2-iodo (2v) groups on the phenyl substituent were
tolerated against potential oxidation or dehalogenation. The
reactions of 1,1-disubstituted alkenes gave lower yields of the
target products (48% for 3w, < 10% for 3x). The reaction of 2y
was successfully scaled up to 2.5 mmol, giving 0.63 g of 3y as
product (61% yield). The latter can be easily deprotected to give
the primary amine 4y. Notably, the majority of the excess
alkene 2y could be recovered (1.23 g, 2.2 equiv.).
Table 1. A brief summary of reaction optimizationsa
O
H
N
1% Ir(ppy)3
O
Troc
15% Cu(OPiv)2 Additive
BzO
NH2
NC
1
0.1 mmol,
Troc
+
NH
Troc
CH3CN, blue LED, 24 h
N2, r.t.
3a
BzO
2a
1 eq.,
2 | J. Name., 2012, 00, 1-3
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The oxidative amination method was then applied on internal amination at the 3 position (5ad, 16% yield). Analogous allylic
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alkenes (Figure 2). The transformation was effective when the alcohols (2ae-2ag) were aminated, with DmOoI:d1e0s.1t0t3o9/gDo0oSCd0y5i9e5l2dHs
alkenes were symmetrically substituted, such as cyclohexene (33% to 61%). The diastereoselectivity was low despite having a
(2z), cyclopentene (2aa), and 4-octene (2ab). The reactions of bulky substituent adjacent to the alcohol group. The reaction of
trans-4-octene and cis-4-octene gave similar yields of 3ab. The a trisubstituted alkene 2ah gave 3ah in 51% yield. The
reaction of an unsymmetrically substituted alkene, e.g., 2- allylamine derivative 2ai reacted to give 3ai in 60% yield. Esters
octene, had a good yield but poor regioselectivity (3ac-1:3ac-2= (2aj and 2ak) reacted to give both allylic amines (3aj and 3ak)
1.4:1). When 2-hexen-1-ol was used as the substrate, amination and aziridines (6aj, 6ak) in similar yields.
at the 2 position (3ad) was dominant (58% yield) compared to
O
1% Ir(dfppy)2(ppy) 10% Cu(OPiv)2
1 eq. Mg(OPiv)2 1 eq. H2O
H
N
2
R
H
O
Troc
1
N
R
+
3
Troc
Ph
H
NC
CH3CN, blue LED, 24 h
N2, r.t.
1
0.1 mmol,
3
2
3 eq.,
3g
n = 6 , 61%
HN
Troc
HN
(52%, cis: trans =1:7)b
CO2H
CnH2n
OH
O
Troc O
HN
3f
3h
= 2 , 57%
X
Troc
HN
Troc
HN
(50%, cis: trans =1:9)b
3a
HN
X = OBz
, 77% (70% cis: trans =1:9)
b
Troc
3i
= 1 , 61% (53%)
3b
3c
= Br , 75% (65%,cis: trans =1:9)
= I , 66% (60%,cis: trans =1:10)
, 59% (54%, cis:
trans =1:12)
= 0, 0%b
a
3d
3e
, 72% (64%)
, 67% (61%)
Troc
Troc
HN
O
HO
Troc
Me
CO2H
Ph
HN
Troc
O
Troc
HN
O
R
O
HN
O
HN
N
N
CO2H
O
H
H
3n
R = cyclohexyl , 59% (54%)
b
b
a
3m
, 51% (45%)
3j
(L)- , 60% (45%)
3k
3l
(L)- , 45% (32%)
, 54% (51%)
3o
= tert-butyl , 62% (57%)
R
Troc
HN
Troc
HN
O
Troc
HN
HN
Troc
Troc
HN
O
O
O
OH
3t
R = H , 54%
3r
, 40% (cis: trans
=4:1, 29% for cis)a
3u
= 4-OH , 43% (38%)
3s
67% (61%)
3p
3q
, 23% (20%)
, 74% (68%)
3v
= 2-I , 55% (51%)
Troc
HN
O
O
2y
3 eq.
O
O
O
O
H
1) Zn, HOAc
N
(1R, 2S, 5R)
Troc
2) HCl
85%
1
2.5 mmol
4y
HCl
NH2
c
c
0.63 g, 61% yield,
2.2 eq, alkene recovered
3w
, 48%(43%)
3x
, <10%
NHTroc
3y
Figure 1. Scope of terminal alkenes for the oxidative amination. Reaction conditions: same as Table 1, Entry 10. NMR yields and isolation yields (in the bracket) are shown. a Reaction
conditions: same as Table 1,Entry 9. b Reaction conditions: same as Table 1, Entry 2. Products were isolated after methylation as esters.c Reaction conditions: Based on Table 1, Entry
9, acetone as solvent.
O
1% Ir(dfppy)2(ppy) 10% Cu(OPiv)2
H
N
R1
R2
H
1 eq. Mg(OPiv)2 1 eq. H2O
O
Troc
N
R2
+
Troc
H
NC
R1
CH3CN, blue LED, 24 h
N2, r.t.
1
0.1 mmol,
2
3 eq.,
3
Troc
Troc
HN
NHTroc
HN
Troc
HN
OH
NHTroc
O
NHTroc
a
NHTroc
3ab
, 55% (50%)
3ac-1 3ac-2
63% ( 1.4:1, 55%)a
+
,
3z
3aa
3ad
5ad
, 16% (dr= 1:1)
, 51% (44%)
, 60% (54%)
from trans-4-octene
52% from cis-octene
,58% (51%)
R
R
R
O
NHTroc
OH
OH
O
NHTs
N
NHTroc
NHTroc
NHTroc
Troc
6aj
3ae
R= propyl,
, 61% (dr= 2.0:1, 53%)
, 33% (dr= 2.6:1, 30%)
, 38% (dr= 2.2:1 33%)
a
, 42% (35%)
6ak
3aj
R= Bz,
, 33% (29%)
3af
=cyclohexyl,
3ag
b
a
, 39% (31%)
3ai
, 60% (47%)
3ah
, 51% (47%)
3ak
= Ac,
, 31% (26%)
=tert-butyl,
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J. Name., 2013, 00, 1-3 | 3
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Figure 2. Scope of internal alkenes for oxidative amination. Reaction conditions: Same as Table 1, Entry 10. NMR yields and isolation yields (in the bracket) are shown. a
View Article Online
DOI: 10.1039/D0SC05952H
Reaction conditions: same as Table 1,Entry 9. b Reaction conditions: Based on Table 1, Entry 9, acetone as solvent.
A preliminary mechanistic study was conducted for the
a)
reaction. First, the fluorescence quenching of Ir(dfppy)2(ppy) by
F3C
F
F
different reagents was probed (Fig. S1). Among all reagents
N
tBu
tBu
N
Ir
N
Ir
NC
N
CN
N
used in the reaction, only 1 and Cu(OPiv)2 could significantly
quench the excited photocatalyst. In the corresponding Stern-
Volmer plots (Fig. S2-3), the slopes, which are proportional to
the quenching coefficients, are 9955 M-1 and 2438 M-1 for 1 and
Cu(OPiv)2, respectively, suggesting 1 as a more efficient
quencher. Additionally, according to cyclic voltammetry (Fig.
S5), the reduction potential of 1 (Ered(1) = -1.43 V vs SCE) is less
negative than the oxidation potential of the excited
photocatalyst (E(IrIV/Ir*)= -1.56 V), indicating that oxidative
quenching of the excited state of Ir(dfppy)2(ppy) by 1 is
thermodynamically downhill. To probe the possibility of energy
transfer between 1 and the excited photocatalyst, we tested the
oxidative amination using Ir(dfCF3ppy)2(dtbbpy) PF6 (dfCF3ppy =
3,5-difluoro-2-[5-(trifluoromethyl)-2-pyridinyl-N]phenyl,
N
N
F
F
CF3
N
F
N
F
N
F
N
F
Ir(dfppy)2(ppy)
E(IrIV/Ir*)= -1.56 V
4CzIPN (not active)
E(P+/P*)= -1.04 V
Ir(dfCF3ppy)2(dtbbpy) PF6 (not active)
E(IrIV/Ir*)= -0.89 V
ET=58.3 kcal/mol
ET=59.0 kcal/mol
ET=60.8 kcal/mol
b)
hydrolysis
BzO
BzO
H
1,2-hydride
O
shift
H
N
( not observed)
H
Troc
BzO
H
1
2a
+
BzO
O
O
(not observed)
CCl3
intramolecular
trapping
N
HN
Troc
Ritter Reaction
dtbbpy= 4,4'-di-tert-butyl-bipyridine) or 4CzIPN (1,2,3,5-
hydrolysis
BzO
NHAc
BzO
N
tetrakis(carbazol-9-yl)-4,6-dicyanobenzene)
as
the
HN
HN
Troc
( not observed)
Troc
photocatalyst (Scheme 2a). These complexes have similar
triplet energies to Ir(dfppy)2(ppy) but they have a less reducing
excited state (-0.89 V16 and -1.04 V17, respectively). No oxidative
amination was observed using these two photosensitizers. This
result indicates energy transfer is not the likely pathway for the
generation of the amidyl radical.
Scheme2. a. Comparison of oxidative quenching potentials and triplet energies of
several photocatalysts. b. Absence of possible subsequent reactions with a
possible carbocation intermediate in the reaction of 1 with 2a.
During the investigation of reaction scope, we observed a
competition between elimination of β-H and cyclization for
substrates with a pendant nucleophilic group (-OH or -NHTs,
2am-2ar; Scheme 2). When there is one carbon between the
alkene and nucleophilic groups, only cyclization was observed
(5am, 5ap). When there are two carbons, only elimination was
observed (3an, 3aq). When there are 3 carbons, cyclization was
favored (5ao, 5ar), yet the product of elimination (3ar) was still
obtained if the nucleophilic group was -OH. CuII species have
been reported to mediate cyclization of alkyl radical with a
nucleophile.19 In the present case, we envisage a Cu-alkyl
species 8 in which the nucleophilic group coordinates to Cu as
the intermediate to cyclization after reductive elimination. The
observation of cyclization products supports the formation of a
Cu-alkyl intermediate upon trapping of the carbon radical by a
Cu species.
Interestingly, when cyclooctadiene 2as was applied as a
substrate (Eq. 3), aziridine 6as was obtained as the main
product (62%) instead of 3as (17%). This result might be
rationalized by the coordination of Cu in 8as by the alkene
moiety. The coordination could shield H1 from accessing the Cu
center so that elimination of H1 is suppressed. Consequently C-
N reductive elimination to give the aziridine product 6as is
favored. This rational might be applicable to explain the
generation of 6aj and 6 ak as in these cases the ester group of
the alkenes could act as a coordinating group. The coordination
of Cu by an internal alkene moiety as in intermediate 8al (Eq. 2)
might rationalize the generation of a skipped diene 3al instead
of a conjugated diene in the reaction of 1 with 2al.
To verify the radical nature of this reaction, 1 equiv. of TEMPO
(TEMPO = 2,2,6,6-Tetramethylpiperidin-1-yl)oxyl) was added to
the reaction mixture of 1 and 2a (Eq. 1). The oxidative amination
product 3a was not obtained, but the TEMPO adduct 7a was
isolated in 17% yield. Additionally, the reaction of substrate 2al
containing a cyclopropyl substituent, which served as a radical
clock, yielded product 3al where the cyclopropyl ring was
opened (Eq.2). These results indicate the formation of a carbon
radical upon amidyl radical addition. It is conceivable that this
carbon radical is further oxidized to a carbon cation en route to
alkene. Nevertheless, in the reaction of 1 with 2a, we did not
observe products that would arise from 1,2-hydride shift,18
intramolecular nucleophilic trapping, or Ritter reaction of a
carbon cation intermedidate (Scheme 2b). This result suggests
a free carbon cation is an unlikely intermediate.
TEMPO
Conditions:
Table 1, Entry 9
BzO
(1)
3a
2a
+
+ 3 eq.
1
+ 1 eq. TEMPO
NH
Troc
7a
0 %
17%
Conditions:
Table 1, Entry 9
Troc
+
C8H17
3al,
N
(2)
1
C10H21
2al
tBu
O
H
O
Cu
3eq.
40%, stereoisomer: 3.7:1
NH
Troc
H
H
C8H17
H
8al
H
4 | J. Name., 2012, 00, 1-3
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H
tBu
Conclusion
View Article Online
DOI: 10.1039/D0SC05952H
O
Cu
Nu
PivO
H
Cu
H
O
8
H
N
CnH2n Nu
N
In summary, by integrating photochemical generation of
H
H
Troc
Nu
Troc
2am 2ar
-
H
H
amidyl radicals with Cu-mediated β-H elimination of alkyl
radical via a tandem photoredox and copper catalysis, we
developed an intermolecular oxidative amination of
unactivated alkenes. The method can be used to synthesize a
wide range of allylic amines, from readily available alkenes, with
high functional group tolerance. The work broadens the scope
of oxidative amination of alkenes via amidyl radical addition.
H
leading to elimination
-NuH =-NHTs n=2
leading to cyclization
-NuH =-NHTs n=3
NHTroc
-NuH =-NHTs n=1
Troc
HN
N
NHTroc
N
NHTs
Ts
Ts
5am
54%
3an
33%
5ao
70%
-NuH =-OH n=1
-NuH =-OH n=2
-NuH =-OH n=3
Troc
HN
HO
NHTroc
Conflicts of interest
There are no conflicts to declare.
Troc
O
HN
Troc
+
OH
HN
O
ap
3aq
3ar
5ar
68%
59% 5
71%
22%
Scheme 3. Reactions of substrates with a tethered nucleophilic group: Competition
between cyclization and elimination. Conditions: same as Table 1, Entry 9.
Acknowledgements
Conditions:
This work is supported by the EPFL. We thank Zhikun Zhang and
Abdusalom Suleymanov for their help in fluorescence
quenching experiments.
Table 1, Entry 9
+
N
Troc
+
1
Troc
(3)
N
H
Troc
PivO
NH
Cu
2as
3 eq.
6as
62%,
3as
17%
H1
8as
H1
Taking into account the above results, we proposed a plausible Notes and references
catalytic cycle (Scheme 4). The reaction starts from the
1
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Troc
O
R
Troc
H
N
R
HN
H
Troc
vs
9
10
L
SET
- 4-CNC6H4CO2
Troc
Cu
H
1
NH
B
IriV
OPiv
CuII
NC
H
H
R
*IrIII
H2
R
H1
O
SET
HN
Cl3C
CuIII
O
8
O
O
tBu
CuI
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IrIII
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+ OPiv
-HOPiv
Troc
N
R
H
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Scheme 4. The proposed reaction mechanism.
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DOI: 10.1039/D0SC05952H
hv
R1
R2
R1
R2
Troc
HN
Cu
PC
H
R2
H
HN
Troc
O
R1
Troc
HN
O
Ar
Excellent tolerance
for functional groups
Terminal& internal
unactivated alkenes
Oxidative amination via amidyl radical addition of unactivated alkenes was realized by dual
photoredox and copper catalysis.
1