Synthesis of 4-boraneyl-1,4-dihydroisoquinolin-3-ones via copper-catalyzed Boron–Hydrogen bond insertion of 4-diazo-1,4-dihydroisoquinolin-3-ones into amine-borane adduct

Article abstract of DOI:10.1016/j.tet.2021.132019

A facile and efficient copper(I)-catalyzed protocol for the synthesis of 4-boraneyl-1,4-dihydroisoquinolin-3-ones via B–H insertion of copper carbenes derived from 4-diazoisoquinolin-3-ones into amine-borane Lewis adduct is reported. The reactions feature a good scope for the 4-diazoisoquinolin-3-ones, mild reaction conditions and high yields. The products are isolated as bench-stable Lewis adducts with Me₃N.

Full text of DOI:10.1016/j.tet.2021.132019

Tetrahedron 84 (2021) 132019
Contents lists available at ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Synthesis of 4-boraneyl-1,4-dihydroisoquinolin-3-ones via copper-
catalyzed BoroneHydrogen bond insertion of 4-diazo-1,4-
dihydroisoquinolin-3-ones into amine-borane adduct
Li Wu, Junrong Chen, Jianwei Xie, Ping Lu**, Yanguang Wang*
Department of Chemistry, Zhejiang University, Hangzhou, 310027, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
A facile and efficient copper(I)-catalyzed protocol for the synthesis of 4-boraneyl-1,4-dihydroisoquinolin-
3-ones via BeH insertion of copper carbenes derived from 4-diazoisoquinolin-3-ones into amine-borane
Lewis adduct is reported. The reactions feature a good scope for the 4-diazoisoquinolin-3-ones, mild
reaction conditions and high yields. The products are isolated as bench-stable Lewis adducts with Me3N.
© 2021 Elsevier Ltd. All rights reserved.
Received 16 December 2020
Received in revised form
4 February 2021
Accepted 8 February 2021
Available online 20 February 2021
Keywords:
Diazo compounds
Organoboranes
Metal carbenes
Copper-catalysis
BeH bond Insertion
1. Introduction
imidates into more stable 4-diazoisoquinolin-3-ones, a class of
cyclic a-diazo amides [9]. Then, several valuable metal-catalyzed
Organoboranes are an important class of reagents and widely
used in organic synthesis [1a,d,e]. They are valuable materials in the
field of organic electronics, as has been demonstrated by the con-
struction of a number of optoelectronic devices [1b,1c]. Conse-
quently, many methods for their preparations have been developed
in the last decades [2aec,3aed,4aed,5aec,6a,b,7aeh]. The com-
mon methods to obtain organoboranes include hydroborations of
alkenes and alkynes [2], CeH bond borylations [3], CdX bond
borylations [4], and BeH bond insertion reactions of carbenes into
boranes [5], and radical boryaltion/cyclization reactions of diynes
and 1,6-enynes [6]. Among these, the BeH bond insertion reactions
of metal carbenes into stable ligated boranes (e.g., NHC-borane
adducts, amine-borane adducts and phosphine-borane adducts)
have been demonstrated to be efficient route to organoboranes and
attracted much attentions in recent years [7].
transformations were achieved using these novel diazo com-
pounds and thus a number of structurally diverse heterocyclic ring
systems (e.g., spiro[cyclopropane-1,40-isochroman]-30-imines, tet-
rahydroisochromeno[3,4-b]azepines, highly fused isoquinoline
scaffolds, isochromeno[4,3-c]pyridazines, etc.) were conveniently
constructed by these transformations [9,10aee,11aec]. As contin-
uation of our works on this chemistry [9,10] we investigated the
BeH bond insertion reaction of metal carbenes in situ generated
from 4-diazoisoquinolin-3-ones, providing a novel class of stable
organoborane reagents with a 1,4-dihydroisoquinolin-3-one skel-
eton. Herein, we describe the results of our efforts.
2. Results and discussion
Initially, Our study began with the model reaction of 4-diazo-2-
tosyl-1,4-dihydroisoquinolin-3(2H)-one 1a and readily accessible
trimethylamine-borane adduct 2 (2.5 equiv) using Cu(CH3CN)4BF4
(5 mol %) as catalyst. After the reaction has been performed in 1,2-
dichloroethane (DCE) at 80 ꢀC for 4 h, (4-trimethylamine-bor-
aneyl)-2-tosyl-1,4-dihydroisoquinolin-3(2H)-one adduct 3a was
isolated in 80% yield (Table 1, Entry 1). The structure of 3a was
unambiguously characterized by its X-ray single crystal analysis
Previously, we prepared 4-diazoisochroman-3-imines through
copper(I)-catalyzed reaction of (2-ethynylphenyl) methanols with
sulfonyl azides [8], and then converted these cyclic
a-diazo
* Corresponding author.
** Corresponding author.
E-mail addresses: pinglu@zju.edu.cn (P. Lu), orgwyg@zju.edu.cn (Y. Wang).
https://doi.org/10.1016/j.tet.2021.132019
0040-4020/© 2021 Elsevier Ltd. All rights reserved.

L. Wu, J. Chen, J. Xie et al.
Tetrahedron 84 (2021) 132019
Table 1
products 3g-3p were produced in 56%~92% yields. In the case
where R2 ¼ CF3, the lowest yield (56%) was obtained maybe due to
the instability of copper carbene intermediate bearing a strong
electron withdrawing CF3 group.
Reaction condition screening.a.
Using the established reaction conditions, we also tested borane
adducts stabilized by pyridine, 2-methylpyridine and 2-ethyl-5-
methylpyridine. In these cases, pyridine-borane adduct 4 (2.5
equiv) gave isolable product 5 in relatively low yield (30%) (Scheme
1), whereas 2-methylpyridine and 2-ethyl-5-methylpyridine
borane adducts resulted in only detectable products based on
HRMS(ESI) analysis.
Based our observations and literature reports [7], we propose a
BeH bond insertion mechanism (Scheme 2). First, the diazo sub-
strate 1a reacts with copper catalyst to form copper complex A,
which generates copper carbene intermediate B with a release of
N2. Subsequently, the copper carbene inserts into the BeH bond of
the amineꢁborane adduct 2 in a concerted manner via transition
state TS. Thus, the final product 1a is generated with the recycli-
zation of copper catalyst.
Entry
Catalyst
Solvent
Equiv of 2
T (oC)
Yield (%)
1
2
3
4
5
6
7
8
Cu(CH3CN)4BF4
Cu(CH3CN)4PF6
Cu(OTf)2
CuCl
CuI
CuBr
Rh2(esp)4
AgOTf
Cu(CH3CN)4PF6
Cu(CH3CN)4PF6
Cu(CH3CN)4PF6
Cu(CH3CN)4PF6
Cu(CH3CN)4PF6
Cu(CH3CN)4PF6
Cu(CH3CN)4PF6
Cu(CH3CN)4PF6
Cu(CH3CN)4PF6
Cu(CH3CN)4PF6
Cu(CH3CN)4PF6
Cu(CH3CN)4PF6
Cu(CH3CN)4PF6
Cu(CH3CN)4PF6
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCM
EA
CHCl3
PhMe
CH3CN
THF
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCE
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.0
2.2
3.0
2.5
2.5
80
80
80
80
80
80
80
80
80
80
80
80
80
80
50
70
90
80
80
80
80
80
80
85
72
19
trace
trace
trace
n.r.
78
56
42
37
62
trace
60
80
85
57
9
10
11
12
13
14
15
16
17
18
19
20
21
22
Our amine-organoborane products were relatively stable during
subsequent transformations and during storage. However, they
could undergo some transformations. For example, the reaction of
3a with N-methyl imidodiacetic acid (6) in DMSO-toluene afforded
compound 8 in 95% yield (Scheme 3). It is believed that this reac-
tion proceeded through a borate intermediate 7 and its tautomer 7′.
65
3. Conclusion
85
78b
85c
In conclusion, we have demonstrated
a facile copper(I)-
a
Reaction conditions: 1a (0.1 mmol), 2 (x equiv), solvent (1 mL), 4 h; Isolated
catalyzed approach to the synthesis of 4-boraneyl-1,4-
dihydroisoquinolin-3-ones from 4-diazoisoquinolin-3-ones. The
reaction proceeded via a BeH insertion of copper carbene inter-
mediate into amine-borane Lewis adduct. This method features a
good scope for the 4-diazoisoquinolin-3-ones, mild reaction con-
ditions and high yields. The products are isolated as bench-stable
Lewis adducts with Me3N. Taking into consideration the re-
activities of organoborane reagents, our borane products would be
found their applications in organic synthesis.
yields.
b
c
Reaction time: 3 h.
Reaction time: 5 h.
[12]. Several other catalysts were screened. Among them,
Cu(CH3CN)4PF6 was found to improve the yield of 3a to 85%
(Table 1, Entry 2). Cu(OTf)2 and CuCl could also catalyze the
transformation but gave lower yield of 3a (Table 1, Entries 3 and 4).
CuI, CuBr, Rh2(esp)4 and AgOTf did not work (Table 1, Entries 5e8).
We then fixed Cu(CH3CN)4PF6 as catalyst and optimized the sol-
vent. Several solvents, such as dichloromethane (DCM), ethyl ace-
tate (EA), chloroform, toluene and acetonitrile, gave a decreased
yield of 3a (Table 1, Entries 9e13), whereas only trace of 3a was
detected when the reaction was performed in THF (Table 1, Entry
14). Subsequently, the reaction temperature was optimized.
Decreasing the reaction temperature led to a decrease in the yield,
while increasing the reaction temperature did not improve the
reaction (Table 1, Entries 15e17). Further investigation suggested
that altering the amount of trimethylamine-borane adduct (Table 1,
Entries 18, 19 and 20) and reaction time (Table 1, Entries 21 and 22)
could not afford better result. Finally, the condition of entry 2 was
chosen as the optimal condition.
4. Experimental
4.1. General information
Melting points were measured on a micro melting point appa-
ratus without correction. NMR spectra were operated at 400 MHz
for 1H NMR, 100 MHz for 13C NMR. 1H NMR chemical shifts were
quoted in parts per million (ppm) referenced to 0.0 ppm for TMS.
13C NMR chemical shifts were reported in ppm referenced to the
center line of a triplet at 77.00 ppm of CDCl3. The abbreviations s
(singlet), d (doublet), t (triplet), q (quartet) and m (multiplet) are
used to describe peak patterns as appropriate. J values were re-
ported in Hz. All high-resolution mass spectrometry (HRMS) data
were recorded on ESI mass spectrometer. Flash column chroma-
tography was performed employing 300e400 mesh silica gel and
the mixture of ethyl acetate (EA) and petroleum ether (PE) was
used as eluent. Unless otherwise mentioned, all solvents and re-
agents were purchased from commercial sources and used as
received.
With the optimized reaction conditions (Table 1, entry 2), we
investigated the substrate scope of diazo compounds 1 (Table 2). In
general, various substituted 4-diazoisoquinolin-3-ones resulted in
a
diversity of 4-boraneyl-1,4-dihydroisoquinolin-3-ones with
moderate to excellent yields (56%e93%). As shown in Table 2, the
sulfonyl group could be tosyl (product 3a), phenylsulfonyl (product
3b), 4-fluorophenylsulfonyl (product 3c), 4-chlorophenylsulfonyl
(product 3d), 4-methoxyphenylsulfonyl (product 3e) and naph-
thalen-2-ylsulfonyl (product 3f). The best result was obtained for
3e (93% yield). The substituents R2 and R3 on the phenyl ring of
isoquinolin-3-ones could be electron-withdrawing group (e.g., F, Cl,
CF3) or electron-donating group (e.g., Me, MeO, OCH2O). Thus,
4-Diazoisoquinolin-3-ones 1 were prepared according to our
previous procedures [8,9].
4.2. Procedure for the preparation of compounds 3, 5 and 8
4.2.1. General procedure for the preparation of compounds 3 and 5
A 15 mL sealed tube was charged with 4-diazoisoquinolin-3-
2

L. Wu, J. Chen, J. Xie et al.
Tetrahedron 84 (2021) 132019
Table 2
Substrate scope of BeH bond insertion reaction of diazo compounds 1a.
a
Reaction conditions: 1 (0.1 mmol), 2 (0.25 mmol), Cu(CH3CN)4PF6 (5 mmol %), DCE (1 mL), 80 ꢀC, 4 h; Isolated yields.
4.2.2. General procedure for the preparation of compounds 8
A 25 mL Schlenk tube was charged with 3a (0.1 mmol), N-
methyliminodiacetic acid (0.2 mmol) and 1 mL solvent (toluene/
DMSO ¼ 5:1) under nitrogen atmosphere. The resulting mixture
was heated to reflux for 4 h. After concentration in vacuo, the
residue was purified by flash column chromatography on silica gel
(petroleum ether/ethyl acetate ¼ 2:1, v/v) to give pure product 8.
Scheme 1. Reaction of 1a with Pyridine-Borane Adduct 4.
4.3. Characterization data
ones 1 (0.1 mmol), trimethylamine-borane adduct 2 (0.25 mmol) or
pyridine-borane adduct
4
(0.25 mmol), Cu(CH3CN)4PF6
4.3.1. 4-(Trimethylamine-boranyl)-2-tosyl-1,4dihydroisoquinolin-
3(2H)-one (3a)
(0.005 mmol), and DCE (1 mL). The reaction mixture was stirred at
80 ꢀC for 4 h. After cooling to room temperature, the resulted
mixture was evaporated under reduced pressure and the residue
was purified by flash column chromatography on a silica gel with
petroleum ether/ethyl acetate (2:1, v/v) to give pure products 3 or 5.
White solid; Yield: 31.6 mg, 85%; Mp: 185.6e186.4 ꢀC. 1H NMR
(400 MHz, CDCl3)
d
7.88e7.83 (m, 2H), 7.23 (d, J ¼ 8.1 Hz, 2H), 7.18
(dt, J ¼ 7.1, 1.8 Hz, 2H), 7.08 (td, J ¼ 7.5, 1.3 Hz, 1H), 6.94e6.92 (m,
1H), 5.25 (d, J ¼ 14.8 Hz, 1H), 5.04 (d, J ¼ 14.8 Hz, 1H), 3.29 (dd,
J ¼ 8.1, 4.2 Hz, 1H), 2.60 (s, 9H), 2.37 (s, 3H), 1.71 (br, 2H). 13C NMR
(100 MHz, CDCl3)
d 178.0, 144.1, 139.9, 137.1, 129.1, 128.2, 127.8,
3

L. Wu, J. Chen, J. Xie et al.
Tetrahedron 84 (2021) 132019
(100 MHz, CDCl3)
d
178.0, 165.3 (d, J ¼ 254 Hz), 139.9, 135.8 (d,
J ¼ 3 Hz), 131.2 (d, J ¼ 10 Hz), 128.9, 127.9, 125.8, 125.3, 124.5, 115.7
(d, J ¼ 2.2 Hz), 52.3, 48.9. IR (film): 3001, 2926, 2380, 1675, 1490,
1352, 1175, 1088, 984, 665 cmꢁ1. HRMS (ESI) m/z calcd for
C
18H22BFN2NaO3Sþ [M þ Naþ]: 399.1320; found: 399.1323.
4.3.4. 4-(Trimethylamine-boranyl)-2-((4-chlorophenyl)sulfonyl)-
1,4-dihydroisoquinolin-3(2H)-one (3d)
White solid; Yield: 29.8 mg, 76%; Mp: 185.8e186.4 ꢀC. 1H NMR
(400 MHz, CDCl3) d 7.95e7.90 (m, 2H), 7.44e7.39 (m, 2H), 7.22e7.18
(m, 2H), 7.09 (td, J ¼ 7.5, 1.3 Hz, 1H), 6.94 (d, J ¼ 8.0 Hz, 1H), 5.23 (d,
J ¼ 14.8 Hz, 1H), 5.03 (d, J ¼ 14.8 Hz, 1H), 3.29 (dd, J ¼ 8.0, 4.1 Hz,
1H), 2.61 (s, 9H), 1.67 (br, 2H). 13C NMR (100 MHz, CDCl3)
d 178.1,
139.8,139.7,138.3,129.8,128.8,128.7,127.9, 125.9,125.3,124.5, 52.3,
49.0. IR (film): 3001, 2925, 2380, 1678, 1489, 1353, 1169, 1091, 984,
669 cmꢁ1. HRMS (ESI) m/z calcd for C18H22BClN2NaO3Sþ [M þ Naþ]:
415.1025; found: 415.1029.
4.3.5. 4-(Trimethylamine-boranyl)-2-((4-methoxyphenyl)
sulfonyl) ꢁ1,4-dihydroisoquinolin-3(2H)- one (3e)
Scheme 2. Proposed BeH Insertion Mechanism for the Formation of 3a.
White solid; Yield: 32.2 mg, 83%; Mp: 170.0e170.5 ꢀC. 1H NMR
(400 MHz, CDCl3)
d 7.94e7.90 (m, 2H), 7.20e7.17 (m, 2H), 7.11e7.05
(m, 1H), 6.98e6.86 (m, 3H), 5.24 (d, J ¼ 14.8 Hz, 1H), 5.02 (d,
J ¼ 14.8 Hz, 1H), 3.81 (s, 3H), 3.29 (dd, J ¼ 8.2, 4.2 Hz, 1H), 2.61 (s,
9H), 1.79 (br, 2H). 13C NMR (100 MHz, CDCl3)
d 178.0, 163.2, 140.0,
131.4,130.5,129.1,127.8,125.8,125.2,124.4,113.6, 55.6, 52.3, 48.9. IR
(film): 2998, 2912, 2380,1674,1490, 1349,1161,1091, 931, 665 cmꢁ1
.
HRMS (ESI) m/z calcd for C19H25BN2NaO4Sþ [M þ Naþ]: 411.1520;
found: 411.1521.
4.3.6. 4-(Trimethylamine-boranyl)-2-(naphthalen-2-ylsulfonyl)-
1,4-dihydroisoquinolin-3(2H)-one (3f)
White solid; Yield: 34.7 mg, 85%; Mp: 180.1e180.7 ꢀC. 1H NMR
(400 MHz, CDCl3)
d
8.60 (d, J ¼ 1.6 Hz, 1H), 7.95 (dd, J ¼ 7.9, 1.5 Hz,
1H), 7.92e7.81 (m, 3H), 7.57 (dddd, J ¼ 16.5, 8.2, 6.9, 1.4 Hz, 2H),
7.24e7.16 (m, 2H), 7.09 (td, J ¼ 7.5, 1.3 Hz, 1H), 6.92 (dd, J ¼ 7.6,
1.2 Hz, 1H), 5.34 (d, J ¼ 14.8 Hz, 1H), 5.10 (d, J ¼ 14.7 Hz, 1H), 3.28
(dd, J ¼ 8.1, 4.1 Hz,1H), 2.53 (s, 9H),1.67 (br, 2H). 13C NMR (100 MHz,
CDCl3)
d 178.0, 140.0, 136.8, 135.0, 131.7, 130.0, 129.4, 129.0, 128.9,
Scheme 3. Transformation of 3a.
128.6, 127.8, 127.7, 127.3, 125.8, 125.3, 124.4, 122.9, 52.2, 49.1. IR
(film): 3058, 2925, 2380, 1674, 1489, 1346, 1168, 1123, 930,
659 cmꢁ1. HRMS (ESI) m/z calcd for C22H25BN2NaO3Sþ [M þ Naþ]:
431.1571; found: 431.1573.
125.9, 125.3, 124.4, 52.4, 48.9, 21.6. IR (film): 3027, 2924, 2379, 1674,
1489, 1348, 1168, 1089, 931, 662 cmꢁ1. HRMS (ESI) m/z calcd for
C
19H25BN2NaO3Sþ [M þ Naþ]: 395.1571; found: 395.1572.
4.3.7. 4-(Trimethylamine-boranyl)-7-fluoro-2-tosyl-1,4-
dihydroisoquinolin-3(2H)-one (3g)
White solid; Yield: 30.0 mg, 77%; Mp: 179.6e180.2 ꢀC. 1H NMR
4.3.2. 4-(Trimethylamine-boranyl)-2-(phenylsulfonyl)-1,4-
dihydroisoquinolin-3(2H)-one (3b)
(400 MHz, CDCl3)
d
7.88e7.83 (m, 2H), 7.25 (d, J ¼ 8.1 Hz, 2H), 7.13
White solid; Yield: 27.2 mg, 76%; Mp: 164.0e164.9 ꢀC. 1H NMR
(dd, J ¼ 8.4, 5.4 Hz,1H), 6.76 (td, J ¼ 8.5, 2.6 Hz, 1H), 6.64 (dd, J ¼ 9.4,
(400 MHz, CDCl3) d 7.99e7.97 (m, 2H), 7.56e7.51 (m, 1H), 7.47e7.43
2.6 Hz, 1H), 5.24 (d, J ¼ 14.7 Hz, 1H), 4.96 (d, J ¼ 14.7 Hz, 1H), 3.25
(dd, J ¼ 8.1, 4.1 Hz, 1H), 2.60 (s, 9H), 2.37 (s, 3H), 1.65 (br, 2H). 19
F
(m, 2H), 7.19 (dt, J ¼ 7.3, 3.4 Hz, 2H), 7.09 (td, J ¼ 7.5, 1.3 Hz, 1H),
6.96e6.92 (m, 1H), 5.26 (d, J ¼ 14.8 Hz, 1H), 5.05 (d, J ¼ 14.7 Hz, 1H),
3.29 (dd, J ¼ 8.0, 4.1 Hz, 1H), 2.58 (s, 9H), 1.64 (br, 2H). 13C NMR
NMR (376 MHz, CDCl3)
d
ꢁ115.13 ~ ꢁ115.19 (m); 13C NMR (100 MHz,
CDCl3)
d
177.3, 162.5 (d, J ¼ 244 Hz), 144.2, 142.6 (d, J ¼ 10.0 Hz),
(100 MHz, CDCl3)
d 178.0, 139.92, 139.88, 133.1, 129.0, 128.5, 128.2,
136.9,129.1,128.2,126.7 (d, J ¼ 9.0 Hz),124.9 (d, J ¼ 2.0 Hz),112.5 (d,
J ¼ 22.0 Hz), 111.2 (d, J ¼ 22.0 Hz), 52.3, 48.2, 21.5. IR (film): 3001,
2926, 2380, 1679, 1489, 1350, 1167, 944, 897, 661 cmꢁ1. HRMS (ESI)
m/z calcd for C19H24BFN2NaO3Sþ [M þ Naþ]: 413.1477; found:
413.1480.
127.8, 125.8, 125.3, 124.4, 52.3, 48.9. IR (film): 3001, 2908, 2380,
1679, 1489, 1351, 1171, 941, 894, 687 cmꢁ1. HRMS (ESI) m/z calcd for
C
18H23BN2NaO3Sþ [M þ Naþ]: 381.1415; found: 381.1415.
4.3.3. 4-(Trimethylamine-boranyl)-2-((4-fluorophenyl)sulfonyl)-
1,4-dihydroisoquinolin-3(2H)-one (3c)
4.3.8. 4-(Trimethylamine-boranyl)-7-chloro-2-tosyl-1,4-
dihydroisoquinolin-3(2H)-one (3h)
White solid; Yield: 30.0 mg, 80%; Mp: 164.1e164.5 ꢀC. 1H NMR
(400 MHz, CDCl3)
d
8.04e7.98 (m, 2H), 7.22e7.18 (m, 2H), 7.15e7.07
White solid; Yield: 31.6 mg, 78%; Mp: 216.2e217.0 ꢀC. 1H NMR
(m, 3H), 6.95 (d, J ¼ 7.5 Hz, 1H), 5.23 (d, J ¼ 14.8 Hz, 1H), 5.04 (d,
(400 MHz, CDCl3)
d
7.87e7.82 (m, 2H), 7.25 (d, J ¼ 8.5 Hz, 3H),
J ¼ 14.8 Hz, 1H), 3.29 (dd, J ¼ 8.1, 4.2 Hz, 1H), 2.63 (s, 9H), 1.57 (br,
7.20e7.13 (m, 2H), 6.86 (d, J ¼ 8.1 Hz, 1H), 5.21 (d, J ¼ 15.0 Hz, 1H),
2H); 19F NMR (376 MHz, CDCl3)
d
ꢁ104.22 ~ ꢁ104.29 (m); 13C NMR
5.00 (d, J ¼ 15.0 Hz, 1H), 3.26 (dd, J ¼ 8.2, 4.2 Hz, 1H), 2.61 (s, 9H),
4

L. Wu, J. Chen, J. Xie et al.
Tetrahedron 84 (2021) 132019
2.38 (s, 3H), 1.58 (br, 2H). 13C NMR (100 MHz, CDCl3)
d
177.4, 144.3,
127.6, 126.5, 125.7, 124.5, 52.3, 48.2, 21.5. IR (film): 3000, 2924,
2380, 1675, 1488, 1350, 1167, 1087, 984, 669 cmꢁ1. HRMS (ESI) m/z
138. 6, 136.8, 130.8, 129.8, 129.1, 128.2, 127.9, 127.2, 125.2, 52.3, 48.3,
21.6. IR (film): 3059, 2921, 2379, 1679, 1486, 1341, 1165, 938, 896,
668 cmꢁ1. HRMS (ESI) m/z calcd for C19H24BClN2NaO3Sþ [M þ Naþ]:
429.1181; found: 429.1186.
calcd for
429.1185.
C
19H24BClN2NaO3Sþ [M
þ
Naþ]: 429.1181; found:
4.3.14. 4-(Trimethylamine-boranyl)-6-methoxy-2-tosyl-1,4-
dihydroisoquinolin-3(2H)-one (3n)
4.3.9. 4-(Trimethylamine-boranyl)-2-tosyl-7-(trifluoromethyl)-1,4-
dihydroisoquinolin-3(2H)-one (3i)
White solid; Yield: 29.2 mg, 73%; Mp: 164.9e165.3 ꢀC. 1H NMR
White solid; Yield: 24.6 mg, 56%; Mp: 225.5e225.9 ꢀC. 1H NMR
(400 MHz, CDCl3)
d
7.88e7.81 (m, 2H), 7.23 (d, J ¼ 8.1 Hz, 2H), 7.10
(400 MHz, CDCl3)
d
7.87 (d, J ¼ 8.4 Hz, 2H), 7.44 (d, J ¼ 6.5 Hz, 2H),
(d, J ¼ 8.2 Hz, 1H), 6.63 (dd, J ¼ 8.3, 2.6 Hz, 1H), 6.47 (d, J ¼ 2.5 Hz,
1H), 5.20 (d, J ¼ 14.6 Hz, 1H), 4.97 (d, J ¼ 14.5 Hz, 1H), 3.76 (s, 3H),
3.24 (dd, J ¼ 8.1, 4.1 Hz, 1H), 2.62 (s, 9H), 2.37 (s, 3H), 1.59 (br, 2H).
7.28e7.24 (d, 2H), 7.04 (d, J ¼ 8.3 Hz, 1H), 5.31 (d, J ¼ 15.1 Hz, 1H),
5.05 (d, J ¼ 15.0 Hz, 1H), 3.36 (dd, J ¼ 8.1, 4.1 Hz, 1H), 2.62 (s, 9H),
2.38 (s, 3H), 1.63 (br, 2H). 19F NMR (376 MHz, CDCl3)
d
ꢁ62.0(s); 13
C
13C NMR (100 MHz, CDCl3)
d 177.9, 159.4, 144.0, 141.5, 137.1, 129.1,
NMR (100 MHz, CDCl3)
d 176.9, 144.39, 144.36, 136.7, 129.7, 129.2,
128.2, 126.3, 121.7, 111.1, 110.0, 55.2, 52.4, 48.4, 21.6. IR (film): 2989,
2925, 2379, 1673, 1489, 1348, 1161, 1091, 931, 666 cmꢁ1. HRMS (ESI)
m/z calcd for C20H27BN2NaO4Sþ [M þ Naþ]: 425.1677; found:
425.1680.
128.3, 126.9, 126.6, 126.2, 124.7 (q, J ¼ 4.0 Hz), 124.2 (q, J ¼ 270 Hz),
122.2 (q, J ¼ 4.0 Hz), 52.4, 48.4, 21.6. HRMS (ESI) m/z calcd for
C
20H24BF3N2NaO3Sþ [M þ Naþ]: 463.1445; found: 463.1445.
4.3.10. 4-(Trimethylamine-boranyl)-7-methyl-2-tosyl-1,4-
dihydroisoquinolin-3(2H)-one (3j)
4.3.15. 8-(Trimethylamine-boranyl)-6-tosyl-5,8-dihydro-[1,3]
dioxolo[4,5-g]isoquinolin-7(6H)-one (3o)
White solid; Yield: 35.5 mg, 92%; Mp: 201.5e202.2 ꢀC. 1H NMR
White solid; Yield: 32.4 mg, 78%; Mp: 210.5e211.4 ꢀC. 1H NMR
(400 MHz, CDCl3)
d
7.87e7.83 (m, 2H), 7.23 (d, J ¼ 8.1 Hz, 2H),
(400 MHz, CDCl3)
(s, 1H), 6.42 (s, 1H), 5.88 (dd, J ¼ 16.5, 1.5 Hz, 2H), 5.13 (d, J ¼ 14.7 Hz,
1H), 4.93 (d, J ¼ 14.6 Hz, 1H), 3.17 (dd, J ¼ 8.2, 4.1 Hz, 1H), 2.59 (s,
d
7.86e7.83 (m, 2H), 7.24 (d, J ¼ 8.2 Hz, 2H), 6.67
7.03e6.97 (m, 2H), 6.82 (d, J ¼ 8.2 Hz, 1H), 5.20 (d, J ¼ 14.8 Hz, 1H),
5.01 (d, J ¼ 14.8 Hz, 1H), 3.25 (dd, J ¼ 8.2, 4.2 Hz, 1H), 2.60 (s, 9H),
2.36 (s, 3H), 2.30 (s, 3H), 1.68 (br, 2H).13C NMR (100 MHz, CDCl3)
9H), 2.37 (s, 3H), 1.67 (br, 2H). 13C NMR (100 MHz, CDCl3)
d 177.9,
d
178.2, 144.0, 137.1, 136.7, 133.8, 129.0, 128.9, 128.5, 128.2, 125.8,
147.3, 144.7, 144.1, 137.0, 133.5, 129.1, 128.1, 121.8, 106.4, 105.9, 100.8,
52.3, 48.6, 21.5. IR (film): 3002, 2921, 2379, 1674, 1482, 1348, 1166,
1089, 936, 845 cmꢁ1. HRMS (ESI) m/z calcd for C20H25BN2NaO5Sþ
[M þ Naþ]: 439.1469; found: 439.1472.
125.7, 52.3, 48.9, 21.5, 20.9. IR (film): 3015, 2922, 2379, 1674, 1488,
1349, 1167, 1089, 926, 661 cmꢁ1. HRMS (ESI) m/z calcd for
C
20H27BN2NaO3Sþ [M þ Naþ]: 409.1728; found: 409.1728.
4.3.11. 4-(Trimethylamine-boranyl)-7-methoxy-2-tosyl-1,4-
dihydroisoquinolin-3(2H)-one (3k)
4.3.16. 4-(Trimethylamine-boranyl)-6-chloro-2-((4-chlorophenyl)
sulfonyl)-1,4-dihydroisoquinolin- 3(2H)-one (3p)
White solid; Yield: 37.0 mg, 92%; Mp: 201.6e202.0 ꢀC. 1H NMR
White solid; Yield: 34.0 mg, 80%; Mp: 76.4e77.2 ꢀC. 1H NMR
(400 MHz, CDCl3)
d
7.88e7.82 (m, 2H), 7.24 (d, J ¼ 8.1 Hz, 2H),
6.87e6.82 (m, 1H), 6.79e6.74 (m, 2H), 5.20 (d, J ¼ 14.9 Hz, 1H), 5.02
(400 MHz, CDCl3)
d 7.94e7.89 (m, 2H), 7.46e7.40 (m, 2H), 7.11 (d,
(d, J ¼ 14.8 Hz, 1H), 3.77 (s, 3H), 3.23 (dd, J ¼ 8.1, 4.2 Hz, 1H), 2.60 (s,
J ¼ 8.1 Hz, 1H), 7.05 (dd, J ¼ 8.1, 2.0 Hz, 1H), 6.93 (d, J ¼ 2.0 Hz, 1H),
5.21 (d, J ¼ 14.8 Hz, 1H), 4.96 (d, J ¼ 14.8 Hz, 1H), 3.24 (dd, J ¼ 7.9,
3.9 Hz, 1H), 2.60 (s, 9H), 1.67 (br, 2H). 13C NMR (100 MHz, CDCl3)
9H), 2.37 (s, 3H), 1.70 (br, 2H). 13C NMR (100 MHz, CDCl3)
d 178.3,
156.7, 144.0, 137.1, 131.8, 130.1, 129.1, 128.2, 126.7, 113.7, 110.7, 55.3,
52.3, 49.0, 21.5. IR (film): 2999, 2924, 2379, 1675, 1501, 1348, 1167,
1089, 944, 664 cmꢁ1. HRMS (ESI) m/z calcd for C20H27BN2NaO4Sþ
[M þ Naþ]: 425.1677; found: 425.1675.
d
177.2, 142.0, 139.8, 138.1, 133.6, 129.8, 128.8, 127.3, 126.5, 125.7,
124.5, 52.3, 48.3. IR (film): 3001, 2925, 2380, 1675, 1487, 1355, 1170,
1090, 920, 668 cmꢁ1. HRMS (ESI) m/z calcd for C18H21BCl2N2NaO3Sþ
[M þ Naþ]: 449.0635; found: 449.0638.
4.3.12. 4-(Trimethylamine-boranyl)-6-fluoro-2-tosyl-1,4-
dihydroisoquinolin-3(2H)-one (3l)
4.3.17. 4-(Pyridine-boranyl)-2-tosyl-1,4-dihydroisoquinolin-3(2H)-
one (5)
White solid; Yield: 35.8 mg, 92%; Mp: 180.5e181.3 ꢀC. 1H NMR
(400 MHz, CDCl3)
d
7.89e7.82 (m, 2H), 7.25 (d, J ¼ 8.1 Hz, 2H), 7.13
White solid; Yield: 11.8 mg, 30%; Mp: 193.9e194.5 ꢀC. 1H NMR
(dd, J ¼ 8.4, 5.5 Hz,1H), 6.76 (td, J ¼ 8.5, 2.6 Hz,1H), 6.64 (dd, J ¼ 9.3,
2.6 Hz, 1H), 5.24 (d, J ¼ 14.7 Hz, 1H), 4.96 (d, J ¼ 14.7 Hz, 1H), 3.25
(dd, J ¼ 8.1, 4.1 Hz, 1H), 2.59 (s, 9H), 2.37 (s, 3H), 1.69 (br, 2H); 19F
(400 MHz, CDCl3) d 8.29e8.25 (m, 2H), 8.01e7.97 (m,1H), 7.89e7.84
(m, 2H), 7.51e7.45 (m, 2H), 7.25 (d, J ¼ 8.0 Hz, 2H), 7.22e7.16 (m,
2H), 7.10 (td, J ¼ 7.4, 1.3 Hz, 1H), 6.93e6.88 (m, 1H), 5.26 (d,
J ¼ 14.7 Hz, 1H), 5.02 (d, J ¼ 14.6 Hz, 1H), 3.14 (t, J ¼ 6.3 Hz, 1H),
NMR (376 MHz, CDCl3)
(100 MHz, CDCl3)
d
ꢁ115.29
~
ꢁ115.35(m); 13C NMR
d
177.3, 162.5 (d, J ¼ 243 Hz), 144.2, 142.6 (d,
3.08e2.38 (br, 2H), 2.40 (s, 3H). 13C NMR (100 MHz, CDCl3)
d 175.3,
J ¼ 8.0 Hz), 136.9, 129.1, 128.2, 126.7 (d, J ¼ 8 Hz), 124.9 (d, J ¼ 3 Hz),
112.5 (d, J ¼ 22.0 Hz), 111.2 (d, J ¼ 21.0 Hz), 52.3, 48.2, 21.5. IR (film):
3001, 2926, 2380,1679,1461,1350,1167,1089, 984, 661 cmꢁ1. HRMS
(ESI) m/z calcd for C19H24BFN2NaO3Sþ [M þ Naþ]: 413.1477; found:
413.1478.
147.4, 143.9, 140.4, 139.4, 137.2, 129.0, 128.5, 127.8, 125.6, 125.5,
125.4,124.5, 48.9, 21.6. IR (film): 3002, 2921, 2380,1682, 1485, 1339,
1167, 1088, 932, 770 cmꢁ1
C
.
HRMS (ESI) m/z calcd for
21H21BN2NaO3Sþ [M þ Naþ]: 415.1258; found: 415.1260.
4.3.13. 4-(Trimethylamine-boranyl)-6-chloro-2-tosyl-1,4-
dihydroisoquinolin-3(2H)-one (3m)
4.3.18. 2-Tosyl-1,4-dihydroisoquinolin-3(2H)-one (8)
White solid; Yield: 28.5 mg, 95%; Mp: 201.1e201.6 ꢀC. 1H NMR
White solid; Yield: 29.6 mg, 73%; Mp: 199.6e200.4 ꢀC. 1H NMR
(400 MHz, CDCl3)
(m, 1H), 5.08 (s, 2H), 3.62 (s, 2H), 2.40 (s, 3H). 13C NMR (100 MHz,
CDCl3) 168.9, 145.0, 135.7, 131.4, 131.3, 129.4, 128.5, 128.4, 127.3,
d 7.92e7.86 (m, 2H), 7.37e7.27 (m, 5H), 7.16e7.13
(400 MHz, CDCl3)
d
7.87e7.81 (m, 2H), 7.25 (d, J ¼ 8.2 Hz, 2H), 7.11
(d, J ¼ 8.1 Hz, 1H), 7.05 (dd, J ¼ 8.1, 2.1 Hz, 1H), 6.92 (d, J ¼ 2.0 Hz,
1H), 5.23 (d, J ¼ 14.9 Hz, 1H), 4.97 (d, J ¼ 14.8 Hz, 1H), 3.24 (dd,
J ¼ 8.0, 4.1 Hz, 1H), 2.60 (s, 9H), 2.37 (s, 3H), 1.68 (br, 2H). 13C NMR
d
127.2, 125.7, 48.7, 40.4, 21.6. IR (film): 2922, 1710, 1595, 1495, 1457,
1350, 1188, 1088, 925, 670 cmꢁ1. HRMS (ESI) m/z calcd for
(100 MHz, CDCl3)
d
177.2, 144.2, 142.1, 136.8, 133.5, 129.1, 128.2,
C
16H15NNaO3Sþ [M þ Naþ]: 324.0665; found: 324.0666.
5

L. Wu, J. Chen, J. Xie et al.
Tetrahedron 84 (2021) 132019
T. Taniguchi, Org. Lett. 22 (2020) 2054e2059;
(b) M. Birepinte, F. Robert, S. Pinet, L. Chabaud, M. Pucheault, Org. Biomol.
Chem. 18 (2020) 3007e3011;
(c) V.D. Nguyen, V.T. Nguyen, S. Jin, H.T. Dang, O.V. Larionov, Tetrahedron 75
(2019) 584e602;
(d) W. Xu, H. Jiang, J. Leng, H.-W. Ong, J. Wu, Angew. Chem. Int. Ed. 59 (2020)
4009e4016.
Declaration of competing interest
The authors declare that they have no known competing
financial interests or personal relationships that could have
appeared to influence the work reported in this paper.
[5] (a) C. Bedel, A. Foucaud, Tetrahedron Lett. 34 (1993) 311e314;
(b) L. Monnier, J.-G. Delcros, B. Carboni, Tetrahedron 56 (2000) 6039e6046;
(c) T. Imamoto, Y. Yamanoi, Chem. Lett. 25 (1996) 705e706.
[6] (a) T. Watanabe, D. Hirose, D.P. Curran, T. Taniguchi, Chem. Eur J. 23 (2017)
5404e5409;
Acknowledgements
This work was financially supported by NSFC (Nos. 21772169
and 21632003).
(b) S.-C. Ren, F.-L. Zhang, J. Qi, Y.-S. Huang, A.-Q. Xu, H.-Y. Yan, Y.-F. Wang,
J. Am. Chem. Soc. 139 (2017) 6050e6053.
€
[7] (a) D. Drikermann, R.S. Moßel, W.K. Al-Jammal, I. Vilotijevic, Org. Lett. 22
Appendix A. Supplementary data
(2020) 1091e1095;
(b) Y. Pang, Q. He, Z.-Q. Li, J.-M. Yang, J.-H. Yu, S.-F. Zhu, Q.-L. Zhou, J. Am.
Chem. Soc. 140 (2018) 10663e10668;
(c) J.-M. Yang, Z.-Q. Li, M.-L. Li, Q. He, S.-F. Zhu, Q.-L. Zhou, J. Am. Chem. Soc.
139 (2017) 3784;
Supplementary data to this article can be found online at
https://doi.org/10.1016/j.tet.2021.132019.
(d) T.H. Allen, D.P.J. Curran, Org. Chem. 81 (2016) 2094e2098;
(e) Q.-Q. Cheng, H. Xu, S.-F. Zhu, Q.-L. Zhou, Hua Hsueh Hsueh Pao 73 (2015)
326;
References
(f) D. Chen, X. Zhang, W.-Y. Qi, B. Xu, M.-H. Xu, J. Am. Chem. Soc. 137 (2015)
5268;
(g) Q.-Q. Cheng, S.-F. Zhu, Y.-Z. Zhang, X.-L. Xie, Q.-L. Zhou, J. Am. Chem. Soc.
135 (2013) 14094e14097;
[1] (For selected reviews, see:). (a) R. Jana, T.P. Pathak, M.S. Sigman, Chem. Rev.
111 (2011) 1417e1492;
(b) C.D. Entwistle, T.B. Marder, Chem. Mater. 16 (2004) 4574e4585;
€
(c) X. Yin, J. Liu, F. Jakle, Chem. Eur J. 26 (2020) 1e15 (For recent examples,
(h) X. Li, D.P. Curran, J. Am. Chem. Soc. 135 (2013) 12076e12081.
[8] A.N. Ren, P. Lu, Y.G. Wang, Chem. Commun. 53 (2017) 3769e3772.
[9] Z.M. Li, J.R. Chen, L. Wu, A.N. Ren, P. Lu, Y.G. Wang, Org. Lett. 22 (2020) 26e30.
[10] (a) Z.M. Li, J.W. Xie, P. Lu, Y.G. Wang, J. Org. Chem. 85 (2020) 5525e5535;
(b) J.R. Chen, Z.M. Li, M. Suleman, Z.B. Wang, P. Lu, Y.G. Wang, Org. Biomol.
Chem. 18 (2020) 7671e7676;
see:);
(d) A. Gevorgyan, M.F. Obst, Y. Guttormsen, F. Maseras, K.H. Hopmann,
A. Bayer, Chem. Sci. 10 (2019) 10072e10078;
(e) R.B. Reddy, P. Dudhe, P. Chauhan, S. Sengupta, V. Chelvam, Tetrahedron 74
(2018) 6946e6953.
[2] (For a recent review, see:). (a) J. Yang, Z. Li, S. Zhu, Chin. J. Org. Chem. 37
(2017) 2481e2497 (For recent examples, see:);
(c) Z.M. Li, L. Wu, B. Chang, P. Lu, Y.G. Wang, Org. Lett. 21 (2019) 1497e1501;
(d) A.N. Ren, B. Lang, J.L. Lin, P. Lu, Y.G. Wang, J. Org. Chem. 82 (2017)
10953e10959;
(b) J.E. Radcliffe, V. Fasano, R.W. Adams, P. You, M. Ingleson, J. Chem. Sci. 10
(2019) 1434e1441;
(c) H. Yoshida, M. Kimura, H. Tanaka, Y. Murashige, I. Kageyuki, I. Osaka, Chem.
Commun. 55 (2019) 5420e5422.
(e) M. Suleman, J.W. Xie, Z.B. Wang, P. Lu, Y.G. Wang, J. Org. Chem. 86 (2021)
455e465, https://doi.org/10.1021/acs.joc.0c02204.
[11] (a) X. Han, F. Gao, C.P. Li, D.Q. Fang, X. Xie, Y. Zhou, H. Liu, J. Org. Chem. 85
(2020) 6281e6294;
(b) Y. Cheng, X. Han, J. Li, Y. Zhou, H. Liu, Org. Chem. Front. 7 (2020)
3186e3192;
(c) B. Wang, X. Han, J. Li, C. Li, H. Liu, Molecules 25 (2020) 2515.
[12] CCDC 2048687 contains supplementary crystallographic data for 3a.
[3] (a) T.S. De Vries, A. Prokofjevs, J.N. Harvey, E. Vedejs, J. Am. Chem. Soc. 131
(2009) 14679e14687;
(b) J.M. Farrell, D.W. Stephan, Angew. Chem. Int. Ed. 54 (2015) 5214e5217;
(c) A. Prokofjevs, E. Vedejs, J. Am. Chem. Soc. 133 (2011) 20056e20059;
(d) C. Cazorla, T.S. De Vries, E. Vedejs, Org. Lett. 15 (2013) 984e987.
[4] (a) K. Takahashi, M. Shimoi, T. Watanabe, K. Maeda, S.J. Geib, D.P. Curran,
6