Selective 1,2-Aminoisothiocyanation of 1,3-Dienes Under Visible-Light Photoredox Catalysis

Article abstract of DOI:10.1002/anie.202014518

Selective three-component 1,2-diamination of 1,3-dienes with concurrent introduction of two orthogonally protected amino groups remains unknown despite its significant synthetic potential. We report herein that reaction of conjugated dienes with N-aminopy

Full text of DOI:10.1002/anie.202014518

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Accepted Article
Title: Selective 1,2-Aminoisothiocyanation of 1,3-Dienes Under Visible
Light Photoredox Catalysis
Authors: Weisi Guo, Qian Wang, and Jieping Zhu
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Selective 1,2-Aminoisothiocyanation of 1,3-Dienes Under Visible
Light Photoredox Catalysis
Weisi Guo,[a, b] Qian Wang,[a] Jieping Zhu*[a]
[a]
Dr. W. Guo, Dr. Q. Wang, Prof. Dr. J. Zhu
Laboratory of Synthesis and Natural Products
Institute of Chemical Sciences and Engineering
Ecole Polytechnique Fédérale de Lausanne
EPFL-SB-ISIC-LSPN, BCH 5304, 1015 Lausanne (Switzerland)
E-mail: jieping.zhu@epfl.ch
Homepage: http://lspn.epfl.ch
[b]
College of Chemistry & Molecular Engineering
Qingdao University of Science & Technology
53 Zhengzhou Road, Qingdao, P. R. China
Supporting information for this article is given via a link at the end of the document.((Please delete this text if not appropriate))
Abstract: Selective three-component 1,2-diamination of 1,3-dienes
with concurrent introduction of two orthogonally protected amino
groups remains unknown in spite of its significant synthetic potential.
We report herein that reaction of conjugated dienes with N-
However, to the best of our knowledge, aminoisothiocyanation of
1,3-dienes has never been reported. As a continuation of our
research program dealing with the development of radical based
difunctionalization of alkenes[21] and remote C(sp3)-H
functionalization,[22] we report herein that reaction of conjugated
dienes 1 with readily available N-aminopyridinium salts 2[23,24]
afforded, under mild visible light photoredox catalytic conditions,
the 1,2-aminoisothiocyanation products 3 in good yields with
excellent chemo- and regio-selectivities (Scheme 1c). Facile
reductive isomerization of allyl thiocyanates to allyl
isothiocyanates under photoredox conditions is evidenced to
account for the observed chemoselectivity.
aminopyridinium
salts
and
TMSNCS
affords
1,2-
aminoisothiocyanation products in a highly chemo- and regio-
selective manner under mild photoredox catalytic conditions.
Mechanistic studies indicate that the facile isomerization of allyl
thiocyanates to allyl isothiocyanates under photocatalytic conditions
is responsible for the selective formation of the observed products.
The mild isomerization protocol is expected to find applications in the
synthesis of allyl isothiocyanates in a broad sense.
a) Annulative 1,2-diamination of 1,3-dienes (Lioyd-Jones Booker-Milburn, Shi, Zhang)
PdX2 (5-10 mol%)
RN
Selective functionalization of 1,3-dienes is a challenging yet
highly valued synthetic transformation as it converts the easily
available chemicals to the highly functionalized molecules.[1] Due
to the omnipresence of nitrogen-containing compounds in
bioactive natural products and pharmaceuticals, the
difunctionalization of 1,3-dienes incorporating an amino or its
equivalent functions has attracted great recent attention. Thus,
p-benzoquinone or O2
R1
NR
+
R1
RHN
NHR
R2
DME, 60 °C
R2
b) Muñiz’s 1,2-diamination of 1,3-dienes: introduction of two identical amino groups
NTs2
PhI(OAc)2 (1.0 equiv)
+
Ts2NH
Ph
Ph
DCM, RT, 73%
NTs2
c) This work: 1,2-aminoisothiocyanation of 1,3-dienes with the introduction of two
orthogonally protected amino groups
diamination,[2,3]
aminothiolation,[4]
amino
aminomethylamination[7]
oxygenation,[5]
and
S
C
N
photocatalyst
Blue LEDs
aminofluorination,[6]
R4 R6
R4
R1
N
R6
R1
aminoalkylation/arylation[8,9] have been developed allowing the
ready access to the highly functionalized alkenes.[10] Despite the
significant progress recorded in this field, selective incorporation
of two easily manipulable and orthogonally protected amino
groups remains challenging. For example, the annulative 1,2-
diamination of conjugated dienes using ureas, diaziridinones
and N,N-ditosyl o-phenylenediamines has been developed into a
powerful synthetic tool for the synthesis of cyclic
ureas/tetrahydroquinazolines. However, the two amino groups of
these reagents have to be protected by the same function in
order to avoid the regioselectivity issue (Scheme 1a). The only
report on the acyclic 1,2-diamination of 1,3-dienes developed by
Muñiz[2d] afforded the products with two identical sulfonamide
groups (Scheme 1b).[11]
N
+
TMSNCS
+
R3
R3
R2
N
DCM, RT
BF4
R5 R7
R2
R5 R7
3
1
2
Scheme 1. Challenges in selective 1,2-diamination of 1,3-dienes: introducing
two orthogonally protected amino groups. Abbreviations: DCM
=
dichloromethane.
We commenced our studies using (E)-1-phenyl-1,3-
butadiene (1a) and N-aminopyridinium salt 2a as model
substrates. Systematic survey of reaction conditions allowed us
to identify the following optimum conditions: fac-Ir(ppy)3 (1.0
mol%) as a photoredox catalyst in dichloromethane (DCM)
under irradiation with blue LEDs at room temperature (Table 1,
entry
1).[25]
Under
these
conditions,
the
1,2-
Isothiocyanate (NCS) and thiocyanate (SCN) are prevalent
functional groups found in natural products and bioactive
compounds.[12,13] They are also important building blocks for the
construction of nitrogen- and sulfur-containing derivatives.[14,15]
aminoisothiocyanation product 3a was formed as single isomer
in 75% isolated yield. While 3a was formed in similar yield with
Ir(ppy)2(dtbbpy)(PF6) (entry 2), other commonly used
photocatalysts, such as Ru(bpy)3Cl2·6H2O and eosin Y, gave
inferior results (entries 2-4). Lower yields of 3a was obtained
when the reaction was performed in MeCN and DCE under
otherwise identical conditions (entries 1 vs 5, 6). Control
Selective thiocyanation of alkenes including dithiocyanation,[16]
[17]
trifluoromethylthiocyanation,
aminothiocyanation[18]
and
thiocyanodiphenylphosphinoylation,[19]
isothiocyanatoalkylthiation[20] of alkenes have been developed.
1
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10.1002/anie.202014518
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experiments revealed that both photoredox catalyst and light are
indispensable for the reaction (entries 7,8). Finally, addition of
TEMPO to the reaction mixture inhibited completely the reaction
(entry 9).
the 1,4-aminoisothiocyanation products were also isolated in
about 25% yields.
The scope of pyridinium salts was next investigated. As it is
seen, the amidyl radicals (RSO2N•R1, RCON•R1, tBuOCON•R1)
derived from the corresponding N-aminopyridinium salts
participated in the reaction to afford the corresponding three-
component adducts (3s-3z) in good yields. The ready formation
of compounds 3x-3z is particularly noteworthy as the primary
amino function could be released easily after removal of N-Boc
group. It is worth noting that only the E-alkene was isolated
when a mixture of E/Z dienes were used as starting materials.
Finally, similar yield of 3a (1.05g, 76%) was obtained when the
reaction was performed at a gram scale.
Tale 1. Optimization of reaction conditions[a]
photocatalyst
Blue LEDs
NCS
Ts
N
+
Ph
Ph
N
DCM, RT
1a
BF4
NMeTs
Me
TMSNCS
2a
3a
N
N
N
N
Ir
Ir
S
N
R4 R6
BF4
R1
C
N
Conditions[a]
N
R4
R1
N
+
R6
tBu
N
N
+
TMSNCS
R3
N
R3
R2
R5 R7
R2
-
PF6
R5 R7
tBu
Ir(ppy)2(dtbbpy)PF6 (P2)
1
2
3
fac-Ir(ppy)3 (P1)
2Cl-
NCS Me
N
Me
NCS Me
NCS Me
N
Cl
N
Br
Br
Ts
Ts
Ts
HO
Br
O
O
N
3e 85%
3f 57%
NCS
R
2+
N
N
NCS Me
N
Br
Me
N
Ru
N
3a R= H, 75%
3b R= F, 67%
3c R= COOMe, 63%
3d R = CF3, 54%
MeO
COOH
MeO
MeO
N
N
Ts
Ts
3g 80%
3h 65%
NCS Me
N
Ru(bpy)3Cl2 (P3)
Eosin Y (P4)
Me
NCS Me
N
Br
NCS Me
Ts
N
Yield 3a (%)[b]
Ts
Ts
Entry
Conditions
Me
Me
Cl
1
2
3
4
5
6
7
8
9
fac-Ir(ppy)3 (P1), DCM
75
72
18
0
3j 72%
3i 74%
3k 69%
Ir(ppy)2(dtbbpy)(PF6) (P2), DCM
Ru(bpy)3Cl2·6H2O (P3), DCM
Eosin Y (P4), DCM
NCS Me
N
NCS Me
N
Ph NCS Me
N
Ph
Ts
Ts
Ph
Ts
Me
O
fac-Ir(ppy)3, CH3CN
65
68
0
3l 56%
3m 56%
NCS Me
3n 70%
fac-Ir(ppy)3, DCE
NCS Me
N
NCS Me
N
No PC, DCM
N
Ph
Ts
Ts
Ph
Ts
Me
fac-Ir(ppy)3, DCE, in the dark
0
Me
3p 75%, d.r. 3:2[b]
3q 34%[c]
3o 65%
fac-Ir(ppy)3, DCE, TEMPO (2.0 equiv)
0
CN
NCS Me
NCS Me
N
NCS Me
N
Ph
[a] Conditions: 1 (0.2 mmol, 2.0 equiv), 2 (0.1 mmol, 1.0 equiv), TMSNCS (0.2
mmol, 2.0 equiv), photocatalyst (0.001 mmol, 0.01 equiv), solvent (1.0 mL),
blue LEDs, room temperature, N2. [b] Isolated yields. Abbreviations: DCE =
dichloroethane; TEMPO = 2,2,6,6-Tetramethyl-1-piperidinyloxy.
N
Ph
Ts
S
Ph
S
Ph
Ph
Ph
O
O
O
O
3r 30%[d]
3s 64%
3t 60%
NCS Bn
NCS Me
N
NCS Me
N
N
Ph
Ts
Ph
Ph
Boc
O
3u 40%
3v 75%
NCS H
3w 35%
With the optimized conditions in hands, we proceeded to
explore the substrate scope of this methodology starting with the
conjugated dienes (Scheme 2). For 1-aryl-1,3-butadienes, the
presence of electron withdrawing (F, Cl, Br, COOMe, and CF3)
and electron donating groups (Me, OMe) at different positions of
the phenyl ring is well tolerated (3a-3j). Naphthalene (3k) and
heterocycle such as benzofuran (3l) are compatible with the
reaction conditions. The 1,1-, 1,2- and 1,3-disubstituted 1,3-
dienes participated in the reaction to afford the corresponding
diamination products (3m-3o) in good yields. Notably,
compound 3o containing a tetrasubstituted carbon was isolated
in 65% yield. Reaction of 1-phenyl-1,3-pentadiene displayed
high chemo- and regio-selectivity to furnish product 3p in 75%
yield as a mixture of two diastereomers (d.r. = 3:2). The lack of
diastereoselectivity in this case is nevertheless not unexpected.
Alkyl substituted dienes, including cyclohexyl and phenethyl
substituted dienes, participated in the reaction to afford 3q and
3r in yields of 34% and 30%, respectively. In these two cases,
NCS H
N
NCS H
N
N
Boc
Ph
Boc
Boc
Me
Cl
3y 65%[e]
3x 53%[e]
3z 41%[e]
Scheme 2. [a] Conditions: 1 (0.2 mmol, 2.0 equiv), 2 (0.1 mmol, 1.0 equiv),
TMSNCS (0.2 mmol, 2.0 equiv), fac-Ir(ppy)3 (0.001 mmol, 0.01 equiv),
dichloromethane (1.0 mL), blue LEDs, room temperature, N2, 12 h. [b] The d.r.
was determined by 1H NMR. [c] The 1,4-aminoisothiocyanation product was
isolated in 24% yield, see SI. [d] The 1,4-aminoisothiocyanation product was
isolated in 25% yield, see SI. [e] 24 h. Abbreviations: Ts = 4-toluenesulfonyl;
Boc = tert-butoxycarbonyl
The chemoselective introduction of isothiocyanate function
in the above 1,2-aminoisothiocyanation reaction is intriguing as
thiocyanation is generally a dominating pathway in related
transformations. [15-19, 22b] To understand the reaction course, the
progress of reaction between 1a, 2a and TMSNCS was
2
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10.1002/anie.202014518
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monitored by 1H NMR spectroscopy and the results are shown in
and 4. However, the latter was cleanly in situ converted to the
Scheme
3a.
The
plot
revealed
that
both
1,2-
former upon extended reaction time.
aminoisothiocyanation and 1,2-aminothiocyanation products 3a
and 4a were formed at the initial stage of the reaction. After 2 h,
all the N-aminopyridinium salt 2a was consumed leading to 3a
and 4a in NMR yields of 56% and 26%, respectively. Continued
irradiation of the reaction mixture led to the gradual conversion
of 4a to 3a. To further confirm this observation, pure
aminothiocyanation product 4y was isolated. Irradiation of a
DCM solution of 4y in the presence of fac-Ir(ppy)3 provided
cleanly the aminoisothiocyanation product 3y. Additional control
experiments indicated that both the photoredox catalyst and the
blue LEDs irradiation are essential for this isomerization
(Scheme 3b).
a) Catalytic cycle
2
SCN
R
N
R3
R1
2
IrIII*
hν
4
R2
N
N
R1
+
NCS
R
N
BF4
R3
R1
2
IrIII
3
TMSNCS
R2
N
N
R1
R2
N
IrIV
A
R3
R1
D
R2
N
R2
N
R3
R1
R3
R1
N
C
B
b) Literature report on the thermal isomerization of allylic thiocyanate at 153 °C
solvent, heating
NCS
Alkyl
SCN
Alkyl
5
6
nitrobenzene
153 °C
+
Ph
SCN
SCN
Ph
NCS
Ph
7
E
8
a
c) Photocatalytic conversion of allyl thiocyanates to allyl isothiocyanates
R2
N
SCN
SCN
2
Ir(III)*
Ir(IV)
R2
N
SCN
R
N
3
R3
Ir(IV)
R1
R3
R1
R3
R1
Ir(III)
C
D
4
Scheme 4. Mechanistic proposal.
SCN Me
N
4a
Ts
Isomerization of allyl thiocyanate is known to be highly
substrate dependent.[26] While 3-alkyl substituted substrates 5
undergo sigmatropic rearrangement to afford isomeric
NCS H
N
SCN H
N
DCM, RT
Boc
Boc
b
isothiocyanates 6, the cinnamyl thiocyanate
7 isomerizes,
Cl
Cl
without 1,3-shift, to cinnamyl isothiocyanate 8 under harsh
conditions (nitrobenzene, 153 °C, Scheme 4b). Detailed
mechanistic studies indicated that the latter reaction went
4y
3y
fac-Ir(ppy)3, blue LEDs, 24 h.
No PC, no blue LEDs, 24 h
No PC, blue LEDs, 24 h
full conversion (> 90% yield)
0%
trace
through
a sequence of ionization to allyl cation E and
thiocyanate followed by regioselective recombination.[26a] The
facile isomerization of 4 to 3 under our mild photoredox catalytic
conditions at room temperature was therefore surprising. We
propose that the excited IrIII* species is capable of reducing the
allylic thiocyanate 4 to the allylic radical C and thiocyanate.
Oxidation of C to the allylic cation D by Ir(IV) followed by regio-
and chemo-selective nucleophilic trapping would then afford 3
as a major product. Repeating the same cycle would afford 3 as
an only isolable product (Scheme 4c). Attempts to trap the SCN-
and the allylic cation D by BnBr and MeOH, respectively, failed
indicating that D might form a tight ion pair with thiocyanate and
the recombination could be a fast process.
Scheme 3. Reaction course of 1a, 2a with TMSNCS monitored by 1H NMR
using 1,3,5-trimethoxybenzene as an internal standard and the results of the
control experiment.
The light ON/OFF experiments showed that the product was
formed only under blue LEDs irradiation (Figure S2). The
quantum yield of the reaction between 1a and 2a was
determined to be 0.11 (see the Supporting Information). These
results indicated that the radical chain mechanism might not be
involved in the reaction. The Stern-Volmer fluorescence
quenching experiments revealed that 2a, but not TMSNCS,
quenched efficiently the excited state of Ir(ppy)3 (Figure S3-S5).
The synthetic utility of these three-component adducts was
next investigated. As it is shown in Scheme 5a, the vicinal
aminoisothiocyanates 3w and 3x underwent one-pot N-
deprotection and intramolecular cyclization to provide 2-
imidazolidinethiones 9 and 10 in yields of 90% and 88%,
respectively. On the other hand, treatment of 3a (in
MeOH/CH2Cl2, v/v = 3/1) and 3x (in MeOH) with odorless 4-
methylbenzene-1,2-dithiol at room temperature (22 °C, 1 h)
afforded selectively protected 1,2-diamines 11 and 12 in yields
of 76% and 83%, respectively.[27] Bis(tributyltin) oxide can also
mediate this transformation to afford 11 and 12, albeit with
reduced yields (50%).[28]
On the basis of the aforementioned results, a plausible
reaction pathway is illustrated in Scheme 4. Reduction of N-
aminopyridinium salt 2 by excited IrIII* species would generate
radical A which underwent fragmentation to afford the nitrogen-
centered radical B and 2,4,6-collidine. Regioselective addition of
radical B to the 1,3-diene would generate the allylic radical C.
Subsequent oxidation of radical
C
by IrIV would afford
carbocation intermediate D with concurrent re-generation of
Ir(III) species. An off-catalytic cycle nucleophilic addition of
TMSNCS to the allylic cation E is highly regioselective, albeit
with low chemoselectivity, to afford
a
mixture of 1,2-
aminoisothiocyanation and 1,2-aminothiocyanation products 3
3
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10.1002/anie.202014518
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COMMUNICATION
S
N
Chen, J. Chen, W. Zhang, Org. Biomol. Chem. 2018, 16, 5618; e) B. N.
Hemric, A. W. Chen, Q. Wang, ACS Catal. 2019, 9, 10070.
D.-F. Lu, C.-L. Zhu, J. D. Sears, H. Xu, J. Am. Chem. Soc. 2016, 138,
11360.
Y. Liu, Y. Xie, H. Wang, H. Huang, J. Am. Chem. Soc. 2016, 138, 4314.
1,4-Aminoalkylation/arylation, see: a) H. Bao, L. Bayeh, U. K. Tambar,
Chem. Sci. 2014, 5, 4863; b) H.-M. Huang, M. Koy, E. Serrano, P. M.
Pflüger, J. L. Schwarz, F. Glorius, Nat. Catal. 2020, 3, 393.
a) D. Xing, D. Yang, Org. Lett. 2013, 15, 4370; b) K. P. S. Cheung, D.
Kurandina, T. Yata, V. Gevorgyan, J. Am. Chem. Soc. 2020, 142, 9932.
NCS R
HN
TFA, DCM
a
b
N
[6]
R
Ph
Boc
Ph
22 °C
9 R = Me, 90%
10 R = H, 88%
3w R = Me
3x R = H
[7]
[8]
R2
N
2
NH2
NCS
R
N
4-methylbenzene-1,2-dithiol
R1
R1
Ph
Ph
MeOH-CH2Cl2 (v/v = 3:1)
for 3a, 22 °C
MeOH for 3x, 22 °C
[9]
3a R1 = Ts, R2 = Me
3x R1 = Boc, R2 = H
11 R1 = Ts, R2 = Me, 76%
12 R1 = Boc, R2 = H, 83%
[10] For selected examples of C-C bond forming processes, see: a) L. Liao,
R. Jana, K. B. Urkalan, M. S. Sigman, J. Am. Chem. Soc. 2011, 133,
5784; b) X. Wu, H.-C. Lin, M.-L. Li, L.-L. Li, Z.-Y. Han, L.-Z. Gong, J. Am.
Chem. Soc. 2015, 137, 13476; c) Y. Xiong, G. Zhang, J. Am. Chem.
Soc. 2018, 140, 2735.
Scheme 5. Post-transformations: Selective transformations of isothiocyanate.
[11] For examples of diamination of alkenes to differently functionalized
diamines, see: a) D. E. Olson, J. Y. Su, D. A. Roberts, J. Du Bois, J. Am.
Chem. Soc. 2014, 136, 13506; b) Z. M. Khoder, C. E. Wong, S. R.
Chemler, ACS Catal. 2017, 7, 4775; c) S. Lee, Y. J. Jang, E. T. Phipps,
H. Lei, T. Rovis, Synthesis 2020, 52, 1247; d) S. Govaerts, L. Angelini,
C. Hampton, L. Malet-Sanz, A. Ruffoni, D. Leonori, Angew. Chem. Int.
Ed. 2020, 59, 15021; Angew. Chem. 2020, 132, 15131.
[12] Selected bioactive compounds containing NCS moiety, see: a) D. Li, Y.
Shu, P. Li, W. Zhang, H. Ni, Y. Cao, Med. Chem. Res. 2013, 22, 3119;
b) S. Giacoppo, M. Galuppo, G. R. De Nicola, R. Lori, P. Bramanti, E.
Mazzon, Bioorg. Med. Chem. 2015, 23, 80; c) A. P. Lawson, M. J. C.
Long, R. T. Coffey, Y. Qian, E. Weerapana, F. E. Oualid, L. Hedstrom,
Cancer Res. 2015, 75, 5130; d) L. Romeo, R. Lori, P. Rollin, P.
Bramanti, E. Mazzon, Molecules 2018, 23, 624.
[13] Selected bioactive compounds containing SCN moiety, see: a) E.
Elhalem, B. N. Bailey, R. Docampo, I. Ujváry, S. H. Szajnman, J. B.
Rodriguez, J. Med. Chem. 2002, 45, 3984; b) S. Dutta, H. Abe, S.
Aoyagi, C. Kibayashi, K. S. Gates, J. Am. Chem. Soc. 2005, 127,
15004; c) M. P. Fortes, P. B. N. da Silva, T. G. da Silva, T. S. Kaufman,
G. C. G. Militão, C. C. Silveira, Eur. J. Med. Chem. 2016, 118, 21.
[14] For a review on isothiocyanates, see: A. K. Mukerjee, R. Ashare, Chem.
Rev. 1991, 91, 1.
In conclusion, we have developed a novel three-component
reaction of TMSNCS, aminopyridinium salts with 1,3-dienes to
access 1,2-aminoisothiocyanation products in a highly chemo-,
and regio-selective manner. The isothiocyanate group can be
converted to the amino group under mild conditions. To the best
of knowledge, this represents the first examples of selective 1,2-
diamination of 1,3-dienes with two easily manipulable and
orthogonally protected amino functions being introduced. A
facile isomerization of allyl thiocyanates to allyl isothiocyanates
under mild photoredox catalytic conditions uncovered during this
study is expected to find applications in the synthesis of allyl
isothiocyanates in a broad sense.
Acknowledgements ((optional))
We thank EPFL (Switzerland), Swiss National Science
Foundation (SNSF 200021-178846/1) for financial supports.
W.G. thanks China Scholarship Council for visiting scholar
fellowship.
[15] For a review on thiocyanates, see: T. Castanheiro, J. Suffert, M.
Donnard, M. Gulea, Chem. Soc. Rev. 2016, 45, 494.
[16] a) A. De Mico, R. Margarita, A. Mariani, G. Piancatelli, Tetrahedron Lett.
1996, 37, 1889; b) M. Bruno, R. Margarita, L. Parlanti, G. Piancatelli, M.
Trifoni, Tetrahedron Lett. 1998, 39, 3847; c) V. Nair, L. G. Nair,
Tetrahedron Lett. 1998, 39, 4585.
Conflict of Interest
[17] Z. Liang, F. Wang, P. Chen, G. Liu, Org. Lett. 2015, 17, 2438.
[18] D. Zhang, H. Wang, C. Bolm, Chem. Commun. 2018, 54, 5772.
[19] Z.-K. Tao, C.-K. Li, P.-Z. Zhang, A. Shoberu, J.-P. Zou, W. Zhang, J.
Org. Chem. 2018, 83, 2418.
The authors declare no conflict of interest.
[20] H. Tian, J. Yu, H. Yang, C. Zhu, H. Fu, Adv. Synth. Catal. 2016, 358,
1794.
Keywords: Alkene difunctionalization • 1,3-diene • amino
isothiocyanation • photoredox catalysis • amidyl radical
[21] a) T. M. Ha, W. Guo, Q. Wang, J. Zhu, Adv. Synth. Catal. 2020, 362,
2205; b) B. Budai, A. Leclair, Q. Wang, J. Zhu, Angew. Chem. Int. Ed.
2019, 58, 10305; Angew. Chem. 2019, 131, 10411; c) X. Bao, T. Yokoe,
T. M. Ha, Q. Wang, J. Zhu, Nat. Commun. 2018, 9, 3725; d) A. Bunescu,
T. M. Ha, Q. Wang, J. Zhu, Angew. Chem. Int. Ed. 2017, 56, 10555;
Angew. Chem. 2017, 129, 10691.
[22] a) Z. Li, R. O. Torres-Ochoa, Q. Wang, J. Zhu, Nat. Commun. 2020, 11,
403; b) X. Bao, Q. Wang, J. Zhu, Angew. Chem. Int. Ed. 2019, 58,
2139; Angew. Chem. 2019, 131, 2161; c) X. Bao, Q. Wang, J. Zhu,
Chem. Eur. J. 2019, 25, 11630; d) R. O. Torres-Ochoa, A. Leclair, Q.
Wang, J. Zhu, Chem. Eur. J. 2019, 25, 9477; e) X. Bao, Q. Wang, J.
Zhu, Nat. Commun. 2019, 10, 769; f) Z. Li, Q. Wang, J. Zhu, Angew.
Chem. Int. Ed. 2018, 57, 13288; Angew. Chem. 2018, 130, 13472.
[23] For recent reviews on pyridinium salts, see: a) S. L. Rössler, B. J. Jelier,
E. Magnier, G. Dagousset, E. M. Carreira, A. Togni, Angew. Chem. Int.
Ed. 2020, 59, 9264; Angew. Chem. 2020, 132, 9350; b) F.-S. He, S. Ye,
J. Wu, ACS Catal. 2019, 9, 8943.
[24] For selected examples on N-aminopyridinium salts, see: a) T. W.
Greulich, C. G. Daniliuc, A. Studer, Org. Lett. 2015, 17, 254; b) K.
Miyazawa, T. Koike, M. Akita, Chem. Eur. J. 2015, 21, 11677; c) J.-N.
Mo, W.-L. Yu, J.-Q. Chen, X.-Q. Hu, P.-F. Xu, Org. Lett. 2018, 20, 4471;
d) W.-L. Yu, J.-Q. Chen, Y.-L. Wei, Z.-Y. Wang, P.-F. Xu, Chem.
Commun. 2018, 54, 1948; e) Y. Moon, B. Park, I. Kim, G. Kang, S.
Shin, D. Kang, M.-H. Baik, S. Hong, Nat. Commun. 2019, 10, 4117; f) Y.
Moon, W. Lee, S. Hong, J. Am. Chem. Soc. 2020, 142, 12420.
[1]
[2]
[3]
a) J. E. Bäckvall, Acc. Chem. Res. 1983, 16, 335; b) H. Y. Cho, J. P.
Morken, Chem. Soc. Rev. 2014, 43, 4368; c) Y. Zhu, G. G. Cornwall, H.
Du, B. Zhao, Y. Shi, Acc. Chem. Res. 2014, 47, 3665; d) Z. Wu, W.
Zhang, Chin. J. Org. Chem. 2017, 37, 2250; e) Y. Xiong, Y. Sun, G.
Zhang, Tetrahedron Lett. 2018, 59, 347; f) X. Wu, L.-Z. Gong, Synthesis
2019, 51, 122.
Selected examples of 1,2-diamination: a) G. L. J. Bar, G. C. Lloyd-
Jones, K. I. Booker-Milburn, J. Am. Chem. Soc. 2005, 127, 7308; b) H.
Du, B. Zhao, Y. Shi, J. Am. Chem. Soc. 2007, 129, 762; c) B. Zhao, X.
Peng, S. Cui, Y. Shi, J. Am. Chem. Soc. 2010, 132, 11009; d) A.
Lishchynskyi, K. Muñiz, Chem. Eur. J. 2012, 18, 2212; e) Z. Wu, K. Wen,
J. Zhang, W. Zhang, Org. Lett. 2017, 19, 2813.
1,4-Diamination, see: a) B. Akermark, J.-E. Bäckvall, K. Löwenborg, K.
Zetterberg, J. Organomet. Chem. 1979, 166, C33; b) C. Martínez, L.
Martínez, J. Kirsch, E. C. Escudero-Adán, E. Martin, K. Muñiz, Eur. J.
Org. Chem. 2014, 2017.
[4]
[5]
C. E. Sleet, U. K. Tambar, Angew. Chem. Int. Ed. 2017, 56, 5536.
Angew. Chem. 2017, 129, 5628.
1,2-Selective, see: a) D. J. Michaelis, M. A. Ischay, T. P. Yoon, J. Am.
Chem. Soc. 2008, 130, 6610; b) H.-C. Shen, Y.-F. Wu, Y. Zhang, L.-F.
Fan, Z.-Y. Han, L.-Z. Gong, Angew. Chem. Int. Ed. 2018, 57, 2372;
Angew. Chem. 2018, 130, 2396; c) K. Wen, Z. Wu, B. Huang, Z. Ling, I.
D. Gridnev, W. Zhang, Org. Lett. 2018, 20, 1608; d) K. Wen, Z. Wu, B.
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[25] For selected reviews on photocatalysis, see: a) J. M. R. Narayanam, C.
R. J. Stephenson, Chem. Soc. Rev. 2011, 40, 102; b) C. K. Prier, D. A.
Rankic, D. W. C. MacMillan, Chem. Rev. 2013, 113, 5322; c) K. L.
Skubi, T. R. Blum, T. P. Yoon, Chem. Rev. 2016, 116, 10035; d) N. A.
Romero, D. A. Nicewicz, Chem. Rev. 2016, 116, 10075; e) J.-R. Chen,
X.-Q. Hu, L.-Q. Lu, W.-J. Xiao, Chem. Soc. Rev. 2016, 45, 2044; f) M.
N. Hopkinson, A. Tlahuext-Aca, F. Glorius, Acc. Chem. Res. 2016, 49,
2261; g) L. Buzzetti, G. E. M. Crisenza, P. Melchiorre, Angew. Chem.
Int. Ed. 2019, 58, 3730; Angew. Chem. 2019, 131, 3768.
[26] a) P. A. S. Smith, D. W. Emerson, J. Am. Chem. Soc. 1960, 82, 3076;
b) J. Gonda, M. Martinková, J. Imrich, Tetrahedron 2002, 58, 1611.
[27] C.-G. Cho, G. H. Posner, Tetrahedron Lett. 1992, 33, 3599.
[28] J. Isac-García, F. G. Calvo-Flores, F. Hernández-Mateo, F. Santoyo-
González, Eur. J. Org. Chem. 2001, 383.
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Angewandte Chemie International Edition
COMMUNICATION
Entry for the Table of Contents
S
C
N
R4 R6
photocatalyst
Blue LEDs
R4
R1
N
R6
R1
N
+
R3
+
BF4
TMS
NCS
N
R2
R3
R2
DCM, RT
R5 R7
R5 R7
A three-component 1,2-aminoisothiocyanation of the conjugated dienes was realized in a highly chemo- and regio-selective manner
using N-aminopyridinium salts as donors of amidyl radicals. A facile isomerization of allyl thiocyanate to allyl isothiocyanate under
photoredox catalytic conditions at room temperature is uncovered.
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6
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