Intermolecular [4 + 2] process of N-acyliminium ions with simple olefins for construction of functional substituted-1,3-oxazinan-2-ones

Article abstract of DOI:10.1016/j.cclet.2021.05.003

An efficient approach to functionalized 4,6-disubstituted-and 4,6,6-trisubstituted-1,3-oxazinan-2-ones skeleton has been developed through the reaction of semicyclic N,O-acetals 4a and 4b with 1,1-disubstituted ethylenes 5 or 8. As a result of such a [4 +

Full text of DOI:10.1016/j.cclet.2021.05.003

ARTICLE IN PRESS
JID: CCLET
[m5G;June 5, 2021;12:2]
Chinese Chemical Letters xxx (xxxx) xxx
Contents lists available at ScienceDirect
Chinese Chemical Letters
journal homepage: www.elsevier.com/locate/cclet
Communication
Intermolecular [4 + 2] process of N-acyliminium ions with simple
olefins for construction of functional substituted-1,3-oxazinan-2-ones
Xiaoli Hana, Xiaodi Niea, Yiman Fenga, Bangguo Wei a,∗, Changmei Sia,∗, Guoqiang Linb
a Institutes of Biomedical Sciences and School of Pharmacy, Fudan University, Shanghai 200433, China
b Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
a r t i c l e i n f o
a b s t r a c t
Article history:
An efficient approach to functionalized 4,6-disubstituted-and 4,6,6-trisubstituted-1,3-oxazinan-2-ones
skeleton has been developed through the reaction of semicyclic N,O-acetals 4a and 4b with 1,1-
disubstituted ethylenes 5 or 8. As a result of such a [4 + 2] cycloaddition process, 4,6,6-trisubstituted-
1,3-oxazinan-2-ones 6aa, 6af-6au, 7ba, 7bf-7bw and 6,6-spiro containing 1,3-oxazinan-2-ones 9ad, 9ae,
10ba-10bg were obtained in 36%-96% yields and with moderate to excellent diastereoselectivities. In ad-
dition, the synthesis of ( )-norallosedamine 12 could be conveniently achieved from the cycloadduct 7bf.
Received 18 March 2021
Revised 1 May 2021
Accepted 6 May 2021
Available online xxx
Keywords:
N-acyliminium ions
Simple olefins
© 2021 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia
Medica, Chinese Academy of Medical Sciences.
Intermolecular [4 + 2] process
Substituted-1,3-oxazinan-2-ones
Spiro
Nitrogen-containing heterocycles are abundant structural motifs
in a large number of alkaloids [1], drug molecules [2] and biolog-
ically active substances [3]. Although significant accomplishments
have been achieved towards the synthesis of various nitrogen het-
erocyclic compounds in the past few decades [4], modern organic
synthesis still demands more efficient and divergent methodolo-
gies to access privileged motifs of biological active compounds [5].
As a prime instance, 1,3-oxazinan-2-ones are not only a core scaf-
fold within natural products [6] and pharmacologically interest-
ing molecules [7], but also widely utilized as key intermediates
[8] in the synthesis of drugs [8c,8f] and bioactive natural prod-
ucts [7b,8g]. Numerous synthetic approaches were reported to ac-
cess various substituted 1,3-oxazinan-2-ones, including halonium-
mediated [6c,9] or metal-catalyzed cyclization [10], intramolecular
Michael addition of functionalized homoallylamines/homoallylic al-
cohols [11], allylic C-H amination [12], and tethered aminohydrox-
ylation of olefins [13]. However, the effective methods to access
6,6-disubstituted-1,3-oxazinan-2-one 1, exemplified with the core
structural unit of biologically active compounds such as anti-HIV
Efavirenz 2 (Merck) [7e] and 11-β-HSD-1 inhibitor 3 [7c], are rare
[14] (Fig. 1).
ophilic reagents. For examples, the reactions of N-acyliminium
ions with olefins could undergo Lewis acid-catalyzed intramolec-
ular addition-cyclization to construct a series of heterocyclic skele-
tons (Fig. 2, Eq. 1) [18]. Intermolecular reactions of N-acyliminium
ions with olefins were also reported [19]. Kobayashi achieved
the ring-opening allylation of semicyclic N,O-acetals with allylic
silanes (Fig. 2, Eq. 2a) [19a]. Later, Zhang developed the inter-
molecular coupling reaction of N-acyliminium ions with styrene
(Fig. 2, Eq. 2b) [19b]. Notably, N-acyliminium ions could serve as
part of electron-deficient dienes, undergoing [4 + 2] cycloaddition
with various dienophiles (alkenes or alkynes) [20,21]. For exam-
ple, Yoshida established a cycloaddition process of N-acyliminium
ions connecting with an alkoxycarbonyl group with alkenes to
afford substituted 1,3-oxazinan-2-one framework, but the forma-
tion of corresponding N-acyliminium dienes required anodic ox-
idation of α-silyl carbamate substrates (Fig. 2, Eq. 3) [20d]. On
the basis of our continuous efforts in exploring chemical trans-
formations of semicyclic N,O-acetals [22], we envisioned that such
[4 + 2] cycloaddition could lead to various important units. Herein
we present an efficient synthetic approach to 4,6,6-trisubstituted-
1,3-oxazinan-2-ones 6/7/9/10 through TMSOTf-mediated [4 + 2]
cycloaddition of semicyclic N,O-acetals 4 with 1,1-disubstituted
ethylenes 5/8 (Fig. 2, Eq. 4).
N-Acyliminium ions, acting as important organic synthetic
intermediates, are widely used in the formation of C-C and
C-heteroatom bonds [15], mostly through intermolecular addi-
tion [16] and intramolecular cyclization [17] with various nucle-
Our investigation started with the reaction of semicyclic N,O-
acetal 4b with 1,1-diphenylethene 5a. The reaction could not take
place in the absence of Lewis acid (Table 1, entry 1). Several types
of iron Lewis acids could lead to only faint products (Table 1, en-
tries 2-6). When Ni(OTf)2, Cu(OTf)2 and Sc(OTf)3 were examined,
∗
Corresponding authors.
E-mail addresses: bgwei1974@fudan.edu.cn (B. Wei), sicm@fudan.edu.cn (C. Si).
https://doi.org/10.1016/j.cclet.2021.05.003
1001-8417/© 2021 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.
Please cite this article as: X. Han, X. Nie, Y. Feng et al., Intermolecular [4 + 2] process of N-acyliminium ions with simple olefins for
construction of functional substituted-1,3-oxazinan-2-ones, Chinese Chemical Letters, https://doi.org/10.1016/j.cclet.2021.05.003

ARTICLE IN PRESS
JID: CCLET
[m5G;June 5, 2021;12:2]
X. Han, X. Nie, Y. Feng et al.
Chinese Chemical Letters xxx (xxxx) xxx
Fig. 1. 6,6-Disubstituted-1,3-oxazinan-2-one scaffold and active compounds.
Scheme 1. The reactions of semicyclic N,O-acetals 4a/4b with olefins 5b-5j. The re-
actions were performed with N,O-acetals 4 (0.5 mmol), olefins 5b-5j (1.0 mmol),
and TMSOTf (1.0 mmol) in dry DCM (2 mL) at -78 °C for 5-10 h, isolated yield. dr
a
was determined by HPLC or NMR of crude products. 7bf (2.80 g, 51% yield) was
obtained with 4b (22.0 mmol), 5f (44.0 mmol), and TMSOTf (44.0 mmol) in dry
DCM (50 mL) at −78°C for 8 h.
no product was observed (Table 1, entries 7-9). SnCl4 could afford
the desired product 7ba in 34% yield (Table 1, entry 10). Slight im-
provements in yields were achieved when TiCl4 and BF3˙Et2O were
applied, and the desired product 7ba could be obtained in mod-
erate yield (48% and 66% respectively, Table 1, entries 11 and 12).
Delightfully, TMSOTf could significantly increase the yield of 7ba to
81% (Table 1, entry 13). It was worth noting that the reaction was
conducted at -78 °C. Either increasing or decreasing the loading of
TMSOTf resulted in slight drop of the reaction yield (Table 1, en-
tries 14 and 15). The reaction could also afford the desired product
using THF and PhMe as solvents, but the corresponding yields were
lower compared with that in dichloromethane (Table 1, entries 16
and 17).
With the above identified optimized reaction conditions, the
olefin substrates 5b-5j with different electronic properties were
examined and the results were summarized in Scheme 1. First,
neither hex-1-ene 5b nor cyclohexene 5c could afford any desired
product in the presence of TMSOTf. The dienophiles with electron-
withdrawing groups, methyl acrylate 5d and (E)-4-phenylbut-3-
en-2-one 5e, led to complicated reaction mixtures. Delightfully,
styrene 5f and its derivatives (5g and 5h) could generate the de-
sired products 6af, 7bf-7bh in moderate yields and diastereose-
lectivities. 2-Vinylnaphthalene could also react with 4a and 4b to
give the corresponding products 6ai and 7bi in moderate yields
and diastereoselectivities. It was worth mentioning that a complex
result was obtained when (E)-1, 2-diphenylethene 5j was investi-
gated, probably due to the steric effect during the intermolecular
[4+2] cycloaddition process.
Fig. 2. The intra- or intermolecular reactions of N-acyliminium ions with olefins.
Table 1
Optimization of reaction conditions.a
Entry
Catalyst (equiv.)
T (°C)
Solvents
Yield (%)b
1
–
r.t.
DCM
DCM
DCM
DCM
DCM
DCM
DCM
DCM
DCM
DCM
DCM
DCM
DCM
DCM
DCM
PhMe
THF
NR
2
FeCl3 (0.2)
0~r.t.
0~r.t.
0~r.t.
0~r.t.
0~r.t.
r.t.
trace
trace
trace
trace
trace
NR
3
FeCl2 (0.2)
4
Fe(OTf)3 (0.2)
Fe(OTf)2 (0.2)
Fe(BF4)3 (0.2)
Ni(OTf)2 (0.2)
Cu(OTf)2 (0.2)
Sc(OTf)3 (0.2)
SnCl4 (2.0)
5
6
7
8
r.t.
NR
9
r.t.
NR
Next, we turned to investigate the scope and limitation of such
addition-cyclization of semicyclic N,O-acetal (4a or 4b) with 1,1-
disubstituted ethylenes 5a, 5k-5v (Scheme 2). When prop-1-en-2-
ylbenzene 5k was explored, desired products 6ak, 7bk were ob-
tained in moderate yields and excellent diastereoselectivities. 4-
Chloro substitution at phenyl ring (5l) led to slight decrease in
yields of 6al, 7bl, but with excellent diastereoselectivities (dr up
to 99:1). Replacement of the methyl group of 5k with other alkyl
substitutions (5q: n-butyl and 5v: isopropyl) was tolerated, and
the desired products 6aq, 7bq, 7bv were afforded in moderate
yields under the optimized conditions. Although the n-butyl sub-
10
11
12
13
14
15
16
17
-78~r.t.
-78~r.t.
-78~r.t.
-78
34
TiCl4 (2.0)
48
BF3.Et2O (2.0)
TMSOTf (2.0)
TMSOTf (1.5)
TMSOTf (3.0)
TMSOTf (2.0)
TMSOTf (2.0)
66
81
-78
74
-78
78
-78
71
-78
51
a
The reaction was performed with 4b (0.5 mmol), 5a (1.0
mmol) and catalyst in solvents (2.0 mL).
b
Isolated yield.
2

ARTICLE IN PRESS
JID: CCLET
[m5G;June 5, 2021;12:2]
X. Han, X. Nie, Y. Feng et al.
Chinese Chemical Letters xxx (xxxx) xxx
Scheme 2. The reactions of semicyclic N,O-acetals 4a/4b with substituted olefins 5a, 5k-5w. The reactions were performed with N,O-acetal 4 (0.5 mmol), olefins (0.75 mmol),
and TMSOTf (1.0 mmol) in dry DCM (2 mL) at -78 °C for 5-10 h. Isolated yield. dr was determined by HPLC or NMR of crude products.
stituted products 6aq, 7bq showed moderate diastereoselectivities,
the isopropyl substituted product 7bv was obtained with excel-
lent diastereoselectivities. In addition, a series of diaryl substituted
alkenes were surveyed under the optimized conditions. In general,
all these substituted alkenes (5a, 5l-5o) could react with semicyclic
N,O-acetals 4a and 4b, affording the desired products 6aa, 6am-
6ao, 7ba, 7bm, 7bp in moderate yields. Several benzyl and phenyl
olefins 5r-5t were also screened, most of them could give the de-
sired products 6ar-6at, 7br-7bt in excellent yields and diastereos-
electivities, except for the p-methoxyphenyl substituted olefin 5r.
Substituted olefin 5u containing phenyl and phenethyl could also
afford the desired products 6au and 7bu in excellent yields with
moderate diastereoselectivities. The methyl and butyl substituted
ethylene 5w could also react with N,O-acetal 4b to afford the de-
sired product 7bw in 40% yield, but the diastereoselectivities was
lower than those of aryl olefins. The chemical structures of 6aa,
6ak-6au, 7ba, 7bk-7bw were unambiguously confirmed based on
the X-ray crystallographic analysis of compound 7bt (see Support-
ing information for detail).
Next, we turned our attention to investigate the reaction of
semicyclic N,O-acetal 4a or 4b with exocyclic olefins 8a-8g, aim-
ing for the formation of 1,3-oxazinan-2-ones containing a spiro
quaternary carbon (Scheme 3). The reaction of 2-methylene-
1,2,3,4-tetrahydronaphthalene 8a with semicyclic N,O-acetal 4b af-
forded the desired product 10ba in 70% yield. The 6-bromo sub-
stituted olefin 8b led to 10bb in slightly lower yield of 65%,
while the 5-methoxy substituted olefin 8c could generate 10bc
in slightly higher yield of 78%. However, the diastereoselectivi-
ties of 10ba-10bc were low. The symmetric olefin, 2-methylene-
2,3-dihydro-1H-indene 8d, also worked well with semicyclic N,O-
Scheme 3. The reactions of semicyclic N,O-acetals 4a/4b with substituted olefins
acetals 4a and 4b, affording the desired products 9ad and 10bd
in moderate yields. Notably, a simple exocyclic olefin methylenecy-
clopentane 8g also worked well, and the corresponding product
10bg was obtained in 60% yield. Regarding olefin substrates with
the exo-double bond adjacent to the phenyl ring, 5-methylene-
6,7,8,9-tetrahydro-5H-benzo[7]annulene 8e bearing a fused seven-
membered ring could lead to the corresponding products in higher
8a-8g. The reactions were performed with N,O-acetal 4 (0.5 mmol), olefins (0.75
mmol), and TMSOTf (1.0 mmol) in dry DCM (2 mL) at -78 °C for 5-10 h. Isolated
yield. dr was determined by HPLC or NMR of crude products.
yields than that of 1-methylene-1,2,3,4-tetrahydronaphthalene 8f
bearing a fused six-membered ring. In detail, the desired products
9ae and 10be were obtained in 70% and 63% yields, while the yield
of 10bf was only 36%. The diastereoselectivities of 9ae, 10be and
3

ARTICLE IN PRESS
JID: CCLET
[m5G;June 5, 2021;12:2]
X. Han, X. Nie, Y. Feng et al.
Chinese Chemical Letters xxx (xxxx) xxx
Declaration of competing interest
The authors declare that they have no known competing finan-
cial interests or personal relationships that could have appeared to
influence the work reported in this paper.
Acknowledgments
We thank the National Natural Science Foundation of China (No.
21772027 to B.-G. Wei and 21702032 to C.-M. Si) for financial sup-
port. The authors also thank Dr. Han-Qing Dong (Arvinas, Inc.) for
helpful suggestions.
Fig. 3. Possible mechanism for the TMSOTf-mediated [4 + 2] cycloaddition process.
Supplementary materials
Supplementary material associated with this article can be
found, in the online version, at doi:10.1016/j.cclet.2021.05.003.
References
[1] (a) C. Bian, J. Wang, X. Zhou, W. Wu, R. Guo, Chem. Biodiversity 17 (2020).
e2000186; (b) T.P. Cushnie, B. Cushnie, A.J. Lamb, Int. J. Antimicrob. Agents 44
(2014) 377–386; (c) T.B. Hua, C. Xiao, Q.Q. Yang, J.R. Chen, Chin. Chem. Lett.
31 (2020) 311–323; (d) X. Liang, X.Z. Yang, L. Chen, et al., Med. Chem. Res. 30
(2021) 1–14; (e) X.D. Wu, X.N. Li, L.Y. Peng, Q.S. Zhao, J. Org. Chem. 85 (2020)
6803–6807; (f) D.D. Zhang, J.B. Xu, Y.Y. Fan, et al., J. Org. Chem. 85 (2020)
3742–3747.
Scheme 4. Synthesis of ( )-Norallosedamine 12. Reagents and conditions: (a) i,
DMP, DCM, r.t., 3 h; ii, Et3SiH/TMSOTf, MeCN, 0 °C to r.t., 40 min, 75% (2 steps);
(b) t-BuOH/toluene (v/v = 1/1), KOH, 85 °C, 30 min, 86%.
[2] (a) N. Kerru, L. Gummidi, S. Maddila, K.K. Gangu, S.B. Jonnalagadda, Molecules
25 (2020) 1909; (b) A.M. Malebari, D. Fayne, S.M. Nathwani, et al., Eur. J. Med.
Chem. 189 (2020) 112050; (c) M. Baiula, P. Galletti, G. Martelli, et al., J. Med.
Chem. 59 (2016) 9721–9742.
[3] (a) A.A. Aly, A.A. Hassan, M.M. Makhlouf, S. Braese, Molecules 25 (2020) 3036;
(b) A.M.S. El-Sharief, Y.A. Ammar, A. Belal, et al., Bioorg. Chem. 85 (2019)
399–412; (c) A.A. Ivashchenko, Y.A. Ivanenkov, A.G. Koryakova, et al., Eur. J.
Med. Chem. 189 (2020) 112064; (d) S. Zhao, C. Pi, Y. Ye, L. Zhao, Y. Wei, Eur. J.
Med. Chem. 180 (2019) 524–535.
10bf were increased slightly, maybe due to the steric hindrance.
The structures of 9ad, 9ae, 10ba-10bg were unambiguously con-
firmed based on the X-ray crystallographic analysis of compound
10bb (see Supporting information for detail).
A possible mechanism for this TMSOTf-mediated [4 + 2] cy-
cloaddition process is presented in Fig. 3 [19a,20d,20f]. When
semicyclic N,O-acetals 4 reacted with alkenes 5, diene type of
N-acyliminium ions Int-1 was first generated under Lewis acid
conditions. The subsequent reaction with alkenes 5 gave a six-
membered intermediate Int-2, which would define the stereo-
chemical outcome and give Int-3. Upon the cleavage of t-butyl
group, the corresponding cycloadducts 6/7/9/10 were produced,
along with the release of 2-methylprop-1-ene.
[4] (a) P. Jain, P. Verma, G. Xia, J.Q. Yu, Nat. Chem. 9 (2017) 140–144; (b) P. Ma-
jumdar, A. Pati, M. Patra, R.K. Behera, A.K. Behera, Chem. Rev. 114 (2014)
2942–2977; (c) P. Singh, R.K. Varshnaya, R. Dey, P. Banerjee, Adv. Synth. Catal.
362 (2020) 1447–1484; (d) H. Matsuzaki, N. Takeda, M. Yasui, et al., Org. Lett.
22 (2020) 9249–9252; (e) Y. He, J. Yang, Q. Liu, X. Zhang, X. Fan, J. Org. Chem.
85 (2020) 15600–15609.
[5] (a) L. Li, Z. Chen, X. Zhang, Y. Jia, Chem. Rev. 118 (2018) 3752–3832; (b) S. Xu,
H.M. Holst, S.B. McGuire, N.J. Race, J. Am. Chem. Soc. 142 (2020) 8090–8096.
[6] (a) G.M. Larson, B.T. Schaneberg, A.T. Sneden, J. Nat. Prod. 62 (1999) 361–363;
(b) F. Taft, K. Harmrolfs, I. Nickeleit, et al., Chem. Eur. J. 18 (2012) 880–886; (c)
R.B. Woodward, B.W. Au-Yeung, P. Balaram, et al., J. Am. Chem. Soc. 103 (1981)
3213–3215; (d) J.M. Cassady, K.K. Chan, H.G. Floss, E. Leistner, Chem. Pharm.
Bull. 52 (2004) 1–26.
[7] (a) W. Yang, Y. Wang, A. Lai, et al., J. Med. Chem. 63 (2020) 7226–7242;
(b) Z. Xu, C.M. Tice, W. Zhao, et al., J. Med. Chem. 54 (2011) 6050–6062;
(c) Y. Zhang, J.P. Wu, G. Li, et al., J. Org. Chem. 81 (2016) 2665–2669; (d)
L. Zhuang, C.M. Tice, Z. Xu, et al., Bioorg. Med. Chem. 25 (2017) 3649–3657;
(e) S.D. Young, S.F. Britcher, L.O. Tran, et al., Antimicrob. Agents Chemother. 39
(1995) 2602–2605.
Finally, we focused on the utility of this intermolecular [4 + 2]
process of N-acyliminium ions with alkenes in the synthesis of bi-
ologically active molecules. Scheme 4 showed a facile synthesis of
norallosedamine 12. As a natural product, norallosedamine 12 was
isolated from both the Sedum and Lobelia inflata plant family, and
have attracted great interest in synthetic chemistry [23]. Starting
from the cycloadduct 7bf, Dess-Martin oxidation (DMP) and subse-
quent reductive amination (Et3SiH/TMSOTf) could produce bicyclic
pyrido [1,2-c][1,3]oxazin-1-one 11 in 75% overall yield. Then the
ring opening (KOH) of 11 resulted in ( ) norallosedamine 12 in
86% yield (dr = 94:6). The spectroscopic and physical data of the
synthetic ( )-norallosedamine 12 were identical to the reported
data [23a]. Norallosedamine 12 could be potentially converted to
other alkaloids of its family by known process [23b,23d].
[8] (a) S.G. Davies, A.C. Garner, P.M. Roberts, et al., Org. Biomol. Chem. 4 (2006)
2753–2768; (b) J.R. Ella-Menye, V. Sharma, G. Wang, J. Org. Chem. 70 (2005)
463–469; (c) J.W. Hilborn, Z.H. Lu, A.R. Jurgens, et al., Tetrahedron Lett 42
(2001) 8919–8921; (d) G.S. Poindexter, K.M. Strauss, Synth. Commun. 23 (1993)
1329–1338; (e) S.C. Schmid, I.A. Guzei, J.M. Schomaker, Angew. Chem. Int. Ed.
56 (2017) 12229–12233; (f) M. Schulze, Synth. Commun. 40 (2010) 3415–3422;
(g) Y.F. Wang, T. Izawa, S. Kobayashi, M. Ohno, J. Am. Chem. Soc. 104 (1982)
6465–6466.
[9] (a) H. Pan, H. Huang, W. Liu, H. Tian, Y. Shi, Org. Lett. 18 (2016) 896–899; (b)
S. Mangelinckx, Y. Nural, H.A. Dondas, et al., Tetrahedron 66 (2010) 4115–4124.
[10] (a) U. Jakob, W. Bannwarth, Tetrahedron Lett 56 (2015) 6340–6344; (b) R. Rob-
les-Machín, J. Adrio, J.C. Carretero, J. Org. Chem. 71 (2006) 5023–5026.
[11] (a) K. Narasaka, Y. Ukaji, S. Yamazaki, Bull. Chem. Soc. Jpn. 59 (1986) 525–533;
(b) M. Hirama, T. Shigemoto, Y. Yamazaki, S. Ito, J. Am. Chem. Soc. 107 (1985)
1797–1798; (c) A.J. Borah, P. Phukan, J. Chem. Sci. 125 (2013) 1503–1510.
[12] S.A. Reed, A.R. Mazzotti, M.C. White, J. Am. Chem. Soc. 131 (2009)
11701–11706.
In summary, we established a novel and efficient approach
for the synthesis of 4,6-disubstituted- and 4,6,6-trisubstituted-1,3-
oxazinan-2-ones 6aa, 6af-6au, 7ba, 7bf-7bw and 6,6-spiro contain-
ing 1,3-oxazinan-2-ones 9ad, 9ae, 10ba-10bg. The Lewis acid TM-
SOTf could activate semicyclic N,O-acetals (4a and 4b), and the re-
sulting N-alkoxycarbonyliminium ions readily underwent a [4 + 2]
cycloaddition process with 1,1-disubstituted ethylenes 5a, 5k-5w
and 8a-8g. The corresponding products were obtained in moderate
to excellent yields and diastereoselectivities. In addition, the utility
of this methodology was demonstrated by the facile synthesis of
natural product ( )-norallosedamine 12 from the cycloadduct 7bf.
[13] T.J. Donohoe, C.J.R. Bataille, W. Gattrell, J. Kloesges, E. Rossignol, Org. Lett. 9
(2007) 1725–1728.
[14] (a) A.J. Boddy, C.J. Cordier, K. Goldberg, et al., Org. Lett. 21 (2019) 1818–1822;
(b) T. Buyck, Q. Wang, J. Zhu, J. Am. Chem. Soc. 136 (2014) 11524–11528; (c)
N. Uddin, J.S. Ulicki, F.H. Foersterling, M.M. Hossain, Tetrahedron Lett 52 (2011)
4353–4356; (d) R. Yousefi, T.J. Struble, J.L. Payne, et al., J. Am. Chem. Soc. 141
(2019) 618–625.
4

ARTICLE IN PRESS
JID: CCLET
[m5G;June 5, 2021;12:2]
X. Han, X. Nie, Y. Feng et al.
Chinese Chemical Letters xxx (xxxx) xxx
[15] (a) A.M. Jones, C.E. Banks, Beilstein J. Org. Chem. 10 (2014) 3056–3072; (b)
U. Martínez-Estibalez, A. Gómez-SanJuan, O. García-Calvo, et al., Eur. J. Org.
Chem. 2011 (2011) 3610–3633; (c) J. Royer, M. Bonin, L. Micouin, Chem. Rev.
104 (2004) 2311–2352; (d) M.G. Vinogradov, O.V. Turova, S.G. Zlotin, Russ.
Chem. Rev. 86 (2017) 1–17; (e) A.K. Sahu, R. Unnava, S. Shit, A.K. Saikia, J. Org.
Chem. 85 (2020) 1961–1971.
[20] (a) S.M. Weinreb, P.M. Scola, Chem. Rev. 89 (1989) 1525–1534; (b)
T. Shimizu, K. Tanino, I. Kuwajima, Tetrahedron Lett 41 (2000) 5715–5718; (c)
D.M. Tomazela, L.A.B. Moraes, R.A. Pilli, M.N. Eberlin, M.G.M. D’Oca, J. Org.
Chem. 67 (2002) 4652–4658; (d) S. Suga, Y. Tsutsui, A. Nagaki, J.I. Yoshida,
Bull. Chem. Soc. Jpn. 78 (2005) 1206–1217; (e) S. Suga, D. Yamada, J.-i. Yoshida,
Chem. Lett. 39 (2010) 404–406; (f) S. Suga, A. Nagaki, Y. Tsutsui, J.I. Yoshida,
Org. Lett. 5 (2003) 945–947.
[16] (a) H.E. Zaugg, Synthesis (1970) 49–73; (b) H.E. Zaugg, Synthesis (1984)
85–110; (c) S. Pyne, A. Yazici, Synthesis
3
(2009) 339–368; (d) A. Yazici,
[21] (a) P.M. Esch, H. Hiemstra, W.N. Speckamp, Tetrahedron Lett 29 (1988)
367–370; (b) P.M. Esch, H. Hiemstra, W. Nico Speckamp, Tetrahedron 48 (1992)
3445–3462.
S.G. Pyne, Synthesis 4 (2009) 513–541; (e) G.M. Ryder, U. Wille, A.C. Willis,
S.G. Pyne, Org. Biomol. Chem. 17 (2019) 7025–7035; (f) T. Thaima, A. Yazici,
C. Auranwiwat, et al., Org. Biomol. Chem. 19 (2021) 259–272.
[23] (a) X.M. Wang, Y.W. Liu, R.J. Ma, C.M. Si, B.G. Wei, J. Org. Chem. 84 (2019)
11261–11267; (b) C. Wang, Z.Y. Mao, Y.W. Liu, et al., Adv. Synth. Catal. 362
(2020) 822–831; (c) R.C. Liu, W. Huang, J.Y. Ma, B.G. Wei, G.Q. Lin, Tetrahedron
Lett 50 (2009) 4046–4049; (d) Y.W. Liu, R.J. Ma, J.H. Yan, Z. Zhou, B.G. Wei, Org.
Biomol. Chem. 16 (2018) 771–779; (e) P. Han, Z.Y. Mao, C.M. Si, et al., J. Org.
Chem. 84 (2019) 914–923; (f) Z.D. Chen, Z. Chen, Q.E. Wang, C.M. Si, B.G. Wei,
Tetrahedron Lett 61 (2020) 152051; (g) X.L. Han, X.D. Nie, Z.D. Chen, et al., J.
Org. Chem. 85 (2020) 13567–13578; (h) Y.X. Zhang, L.Y. Chen, J.T. Sun, C.M. Si,
B.G. Wei, J. Org. Chem. 85 (2020) 12603–12613.
[22] (a) B.A.D. Neto, A.A.M. Lapis, A.B. Bernd, D. Russowsky, Tetrahedron 65 (2009)
2484–2496; (b) R.A. Pilli, L.C. Dias, Synth. Commun. 21 (1991) 2213–2229; (c)
B.V.Subba Reddy, S. Ghanty, N.S.S. Reddy, Y.J. Reddy, J.S. Yadav, Synth. Com-
mun. 44 (2014) 1658–1663; (d) C.Y. Yu, O. Meth-Cohn, Tetrahedron Lett 40
(1999) 6665–6668; (e) J.S. Yadav, Y.Jayasudhan Reddy, P. Adi Narayana Reddy,
B.V. Subba Reddy, Org. Lett. 15 (2013) 546–549.
[17] P. Wu, T.E. Nielsen, Chem. Rev. 117 (2017) 7811–7856.
[18] (a) M. Das, A.K. Saikia, J. Org. Chem. 83 (2018) 6178–6185; (b) K. Indukuri,
R. Unnava, M.J. Deka, A.K. Saikia, J. Org. Chem. 78 (2013) 10629–10641; (c)
Y. Krishna, K. Shilpa, F. Tanaka, Org. Lett. 21 (2019) 8444–8448; (d) Y. Zheng,
L. Andna, O. Bistri, L. Miesch, Org. Lett. 22 (2020) 6771–6775; (e) S. Hanessian,
M. Tremblay, Org. Lett. 6 (2004) 4683–4686; (f) S. Hanessian, M. Tremblay,
J.F.W. Petersen, J. Am. Chem. Soc. 126 (2004) 6064–6071.
[19] (a) M. Sugiura, H. Hagio, R. Hirabayashi, S. Kobayashi, Synlett 2001 (2001)
1225–1228; (b) N. Lu, L. Wang, Z. Li, W. Zhang, Beilstein J. Org. Chem. 8 (2012)
192–200; (c) H. Richter, R. Frohlich, C.G. Daniliuc, O. Garcia Mancheno, Angew.
Chem., Int. Ed. 51 (2012) 8656–8660; (d) A. Yazici, U. Wille, S.G. Pyne, J. Org.
Chem. 81 (2016) 1434–1449.
5