3
36 References and Notes
MeO
ClCOOMe
light
37
38
39
40
1
2
Hagel, J. M.; Facchini, P. J. Plant Cell Physiol. 2013, 54, 647.
Todorov, D.; Hinkov, A.; Shishkova, K.; Shishkov, S.
Phytochem. Rev. 2014, 13, 525. Also see the references sited
therein.
Fujiwara, N.; Ueda, Y.; Ohashi, N. Bioorg. Med. Chem. Lett.
1996, 6, 743.
Suzuki, Y.; Saito, Y.; Goto, M.; Newman, D. J. ; O’Keefe, B. R.;
N
1b + 2d
MeO
MeO
COOMe
Me
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
3
4
5
6
7
3bd quant
MeO
Me
Me
N
Lee, K.-H.; Nakagawa-Goto, K. J. Nat. Prod. 2017, 80, 220.
Chang, G.-J.; Su, M.-J.; Hung, L.-M.; Lee, S.-S. Br. J.
Pharmacol. 2002, 136, 459.
Siatka, T.; Adamcová, M.; Opletal, L.; Cahlíková, L.; Jun, D.;
Scheme 5. Photoreaction between 1b and 2d in the presence
of 2,4,6-collidine.
Hrabinová, M.; Kuneš, J.; Chlebek, J. Molecules 2017, 22, 1181.
a) Chrzanowska, M.; Grajewska, A.; Rozwadowska, M. D. Chem.
Rev. 2016, 116, 12369. b) Barker, A. C.; Battersby, A. R. J.
Chem. Soc. (C) 1967, 1317. c) Rice, K. C.; Ripka, W. C.; Reden,
J.; Brossi, A. J. Org. Chem. 1980, 45, 601. d) Nomoto, T.;
Takayama, H. J. Chem. Soc., Chem. Commun. 1982, 1113. e)
Johnson, A. P.; Luke, R. W. A.; Singh, G.; Boa, A. N. J. Chem.
Soc., Perkin Trans. 1 1996, 907. f) Munchhof, M. J.; Meyers, A.
I. J. Org. Chem. 1996, 61, 4607. g) Fujiwara, N.; Ueda, Y.;
Ohashi, N. Bioorg. Med. Chem. Lett. 1996, 6, 743. h)
Pabuccuoglu, V.; Hesse, M. Heterocycles 1997, 45, 1751. i)
Orito,K.; Satoh, Y.; Nishizawa, H.; Harada, R.; Tokuda, M. Org.
Lett. 2000, 2, 2535. j) Ruchirawat, S.; Namsa-aid, A.
Tetrahedron Lett. 2001, 42, 1359. k) Dragoli, D. R.; Burdett, M.
T.; Ellman, J. A. J. Am. Chem. Soc. 2001, 123, 10127. l) Youte,
J.-J.; Barbier, D.; Al-Mourabit, A.; Gnecco, D.; Marazano, C. J.
Org. Chem. 2004, 69, 2737.
Nishigaichi, Y.; Orimi, T.; Koyachi, K.; Ohmuro, Y.; Suzuki, M.
Chem. Lett. 2016, 45, 1382.
a) Giroux, A. Tetrahedron Lett. 2003, 44, 233. b) Ishiyama, T.;
Oohashi, Z.; Ahiko, T.; Miyaura, N. Chem. Lett. 2002, 780.
A similar preparative method for 2b was reported in the
following literature: Tellis, J. C.; Primer, D. N.; Molander, G. A.
Science 2014, 345, 433.
Inglis, S. R.; Woon, E. C. Y.; Thompson, A. L.; Schofield, C. J. J.
Org. Chem. 2010, 75, 468.
1
2
3
4
5
6
7
8
9
reaction system inhibited the cyclization completely. For
example, when 2,4,6-collidine was added to the reaction
between 1b and 2d, the uncyclized product 3bd was
obtained in a quantitative yield under otherwise the same
conditions (Scheme 5). This result is also of synthetic value
in controlling the reaction path, because the uncyclized
benzylisoquinoline skeleton is another common structure in
the natural products.
Furthermore, when isolated 3bd was exposed to
10 conditions containing 10 mol% of BF3 in acetonitrile, a
11 complex mixture was obtained without formation of 4bd.
12 However, in the presence of both BF3 and water,
13 quantitative formation of 4bd was observed. These results
14 indicated undoubtedly that proton was required as a catalyst
15 for the cyclization, but not BF3 alone that could be generated
16 from 2 during the reaction. The initial proton source is not
17 entirely certain but the trace amount of water in the reaction
18 mixture is the most probable.
8
9
69 10
70
71
72 11
73
19
Finally, argemonine and eschscholtzidine were easily
74
20 obtained by the reduction of 4bd and 4cd, respectively, with
21 LiAlH4 (Scheme 5). After all, by using electron-rich
22 benzyltrifluoroborate 2 as a key reagent, a very facile
23 method for the construction of characteristic pavine alkaloid
24 skeleton was developed. Syntheses of other pavine alkaloids
25 will be available applying appropriate combinations of
26 isoquinoline and benzyltrifluoroborate and are now in
27 progress in our laboratory.
28
MeO
MeO
OMe
OMe
N
Me
LiAlH4
THF
argemonine, 64 %
4bd
4cd
OMe
OMe
O
O
N
Me
eschscholtzidine, 41 %
Scheme 6. Reduction of carbamate moiety.
Information is available
29
30
31
32
33 Supporting
on
34 http://dx.doi.org/10.1246/cl.******.
35