Octahedral Chiral-at-Metal Iridium Catalysts: Versatile Chiral Lewis Acids for Asymmetric Conjugate Additions

Chemistry - A European Journal

Volumn 21, Issue 27, 2015, Pages 9720-9726

  Shen, Xiaodong ^a   Huo, Haohua ^a   Wang, Chuanyong ^a   Zhang, Bo ^a   Harms, Klaus ^a   Meggers, Eric ^a,b  

^a PHILIPPS UNIVERSITY MARBURG   (Germany)

^b XIAMEN UNIVERSITY   (China)

Author keywords

asymmetric catalysis; chiral at metal; conjugate addition; iridium; Lewis acid

Indexed keywords

ADDITION REACTIONS; CARBONYL COMPOUNDS; CATALYSTS; IRIDIUM; LIGANDS; UNSATURATED COMPOUNDS;

ASYMMETRIC CATALYSIS; ASYMMETRIC CATALYSTS; ASYMMETRIC CONJUGATE ADDITION; BIDENTATE COORDINATION; CONJUGATE ADDITION; FRIEDEL-CRAFTS ALKYLATION; LEWIS ACID; UNSATURATED CARBONYL COMPOUNDS;

IRIDIUM COMPOUNDS;

EID: 84935029490     PISSN: 09476539     EISSN: 15213765     Source Type: Journal    
DOI: 10.1002/chem.201500922     Document Type: Article

References (181)

1. P. J. Walsh, M. C. Kozlowski, Fundamentals of Asymmetric Catalysis; University Science Books, Sausalito, California, 2009.
2. J.-L. Pierre, Coord. Chem. Rev. 1998, 178-180, 1183-1192
3. U. Knof, A. von Zelewsky, Angew. Chem. Int. Ed. 1999, 38, 302-322
4. Angew. Chem. 1999, 111, 312-333
5. P. D. Knight, P. Scott, Coord. Chem. Rev. 2003, 242, 125-143
6. H. Amouri, M. Gruselle, Chirality in Transition Metal Chemistry, Wiley, Chichester, UK, 2008
7. E. Meggers, Eur. J. Inorg. Chem. 2011, 2911-2926
8. J. Crassous, Chem. Commun. 2012, 48, 9684-9692
9. E. C. Constable, Chem. Soc. Rev. 2013, 42, 1637-1651.
10. H. Brunner, Angew. Chem. Int. Ed. 1999, 38, 1194-1208
11. Angew. Chem. 1999, 111, 1248-1263
12. C. Ganter, Chem. Soc. Rev. 2003, 32, 130-138
13. M. Fontecave, O. Hamelin, S. Ménage, Top. Organomet. Chem. 2005, 15, 271-288
14. E. B. Bauer, Chem. Soc. Rev. 2012, 41, 3153-3167
15. L. Gong, L.-A. Chen, E. Meggers, Angew. Chem. Int. Ed. 2014, 53, 10868-10874
16. Angew. Chem. 2014, 126, 11046-11053.
17. E. Meggers, Chem. Eur. J. 2010, 16, 752-758.
18. First report:, L. Gong, S. P. Mulcahy, K. Harms, E. Meggers, J. Am. Chem. Soc. 2009, 131, 9602-9603. For a recent account, see
19. L. Gong, M. Wenzel, E. Meggers, Acc. Chem. Res. 2013, 46, 2635-2644.
20. C. Wang, L.-A. Chen, H. Huo, X. Shen, K. Harms, L. Gong, E. Meggers, Chem. Sci. 2015, 6, 1094-1100.
21. M. Helms, Z. Lin, L. Gong, K. Harms, E. Meggers, Eur. J. Inorg. Chem. 2013, 4164-4172.
22. L.-A. Chen, W. Xu, B. Huang, J. Ma, L. Wang, J. Xi, K. Harms, L. Gong, E. Meggers, J. Am. Chem. Soc. 2013, 135, 10598-10601
23. L.-A. Chen, X. Tang, J. Xi, W. Xu, L. Gong, E. Meggers, Angew. Chem. Int. Ed. 2013, 52, 14021-14025
24. Angew. Chem. 2013, 125, 14271-14275
25. J. Ma, X. Ding, Y. Hu, Y. Huang, L. Gong, E. Meggers, Nat. Commun. 2014, 5, 4531
26. H. Huo, C. Fu, C. Wang, K. Harms, E. Meggers, Chem. Commun. 2014, 50, 10409-10411.
27. K. Narasaka, Synthesis 1991, 1-11
28. S. Saito, H. Yamamoto, Chem. Commun. 1997, 1585-1592
29. K. A. Jørgensen, M. Johannsen, S. Yao, H. Audrain, J. Thorhauge, Acc. Chem. Res. 1999, 32, 605-613
30. J. S. Johnson, D. A. Evans, Acc. Chem. Res. 2000, 33, 325-335
31. G. Desimoni, G. Faita, K. A. Jørgensen, Chem. Rev. 2006, 106, 3561-3651
32. S. Kobayashi, C. Ogawa, Chem. Eur. J. 2006, 12, 5954-5960
33. S. Kanemasa, M. Hasegawa, F. Ono, Chem. Rec. 2007, 7, 137-149
34. J. Christoffers, G. Koripelly, A. Rosiak, M. Rössle, Synthesis 2007, 1279-1300
35. M. North, D. L. Usanov, C. Young, Chem. Rev. 2008, 108, 5146-5226
36. P. Li, H. Yamamoto, Top. Organomet. Chem. 2011, 37, 161-183
37. J. Zhou, Y. Tang, Top. Organomet. Chem. 2011, 36, 287-312
38. L. C. Dias, E. C. de Lucca Jr., M. A. B. Ferreira, E. C. Polo, J. Braz. Chem. Soc. 2012, 23, 2137-2158
39. H. Yamamoto, Top. Organomet. Chem. 2013, 44, 315-334.
40. H. Huo, C. Fu, K. Harms, E. Meggers, J. Am. Chem. Soc. 2014, 136, 2990-2993.
41. H. Huo, X. Shen, C. Wang, L. Zhang, P. Röse, L.-A. Chen, K. Harms, M. Marsch, G. Hilt, E. Meggers, Nature 2014, 515, 100-103.
42. A new redox condensation was used for the synthesis of benzothiazoles, see:, T. B. Nguyen, L. Ermolenko, P. Retailleau, A. Al-Mourabit, Angew. Chem. Int. Ed. 2014, 53, 13808-13812
43. Angew. Chem. 2014, 126, 14028-14032.
44. For related cyclometalation reactions with 2-phenylbenzothiazoles, see:, S. Lamansky, P. Djurovich, D. Murphy, F. Abdel-Razzaq, R. Kwong, I. Tsyba, M. Bortz, B. Mui, R. Bau, M. E. Thompson, Inorg. Chem. 2001, 40, 1704-1711.
45. P. Paredes, J. Díez, M. P. Gamasa, Organometallics 2008, 27, 2597-2607
46. C. P. Owens, A. Varela-Álvarez, V. Boyarskikh, D. G. Musaev, H. M. L. Davies, S. B. Blakey, Chem. Sci. 2013, 4, 2590-2596
47. D. Carmona, J. Ferrer, N. García, P. Ramírez, F. J. Lahoz, P. García-Orduña, L. A. Oro, Organometallics 2013, 32, 1609-1619
48. Y. Kita, K. Yamaji, K. Higashida, K. Sataiah, A. Iimuro, K. Mashima, Chem. Eur. J. 2015, 21, 1915-1927.
49. D. A. Evans, K. R. Fandrick, H.-J. Song, J. Am. Chem. Soc. 2005, 127, 8942-8943
50. D. A. Evans, K. R. Fandrick, H.-J. Song, K. A. Scheidt, R. Xu, J. Am. Chem. Soc. 2007, 129, 10029-10041
51. A. J. Boersma, B. L. Feringa, G. Roelfes, Angew. Chem. Int. Ed. 2009, 48, 3346-3348
52. Angew. Chem. 2009, 121, 3396-3398
53. C. Wang, Y. Li, G. Jia, Y. Liu, S. Lu, C. Li, Chem. Commun. 2012, 48, 6232-6234
54. J. Wang, E. Benedetti, L. Bethge, S. Vonhoff, S. Klussmann, J.-J. Vasseur, J. Cossy, M. Smietana, S. Arseniyadis, Angew. Chem. Int. Ed. 2013, 52, 11546-11549
55. Angew. Chem. 2013, 125, 11760-11763.
56. D. A. Evans, K. R. Fandrick, Org. Lett. 2006, 8, 2249-2252.
57. For comparison, a DNA-based copper(II) catalyst (30 mol %) provided for the same malonodinitrile Michael addition product with an enantioselectivity of 36 % ee at 4 C, see:, Y. Li, C. Wang, G. Jia, S. Lu, C. Li, Tetrahedron 2013, 69, 6585-6590.
58. C. J. Douglas, L. E. Overman, Proc. Natl. Acad. Sci. USA 2004, 101, 5363-5367
59. J. Christoffers, A. Baro, Adv. Synth. Catal. 2005, 347, 1473-1482
60. B. M. Trost, C. Jiang, Synthesis 2006, 369-396
61. M. Bella, T. Gasperi, Synthesis 2009, 1583-1614
62. C. Hawner, A. Alexakis, Chem. Commun. 2010, 46, 7295-7306
63. J. P. Das, I. Marek, Chem. Commun. 2011, 47, 4593-4623
64. R. Dalpozzo, G. Bartoli, G. Bencivenni, Chem. Soc. Rev. 2012, 41, 7247-7290
65. K. W. Quasdorf, L. E. Overman, Nature 2014, 516, 181-191.
66. For comparison, a bis(oxazolinyl)pyridine-cerium(IV) triflate catalyst provided for the same nitrone cycloaddition reaction 99 % yield with 97 % ee and >99:1 endo/exo with 5 mol % catalyst at 0 C, see:, D. A. Evans, H.-J. Song, K. R. Fandrick, Org. Lett. 2006, 8, 3351-3354.
67. K. V. Gothelf, K. A. Jørgensen, J. Org. Chem. 1994, 59, 5687-5691
68. K. V. Gothelf, I. Thomsen, K. A. Jørgensen, J. Am. Chem. Soc. 1996, 118, 59-64
69. S. Kobayashi, M. Kawamura, J. Am. Chem. Soc. 1998, 120, 5840-5841
70. S. Kanemasa, Y. Oderaotoshi, J. Tanaka, E. Wada, J. Am. Chem. Soc. 1998, 120, 12355-12356
71. C. Palomo, M. Oiarbide, E. Arceo, J. M. García, R. Lõpez, A. González, A. Linden, Angew. Chem. Int. Ed. 2005, 44, 6187-6190
72. Angew. Chem. 2005, 117, 6343-6346
73. M. P. Sibi, Z. Ma, K. Itoh, N. Prabagaran, C. P. Jasperse, Org. Lett. 2005, 7, 2349-2352
74. K. Phomkeona, T. Takemoto, Y. Ishima, K. Shibatomi, S. Iwasa, H. Nishiyama, Tetrahedron 2008, 64, 1813-1822
75. S. Barroso, G. Blay, M. C. Muñoz, J. R. Pedro, Org. Lett. 2011, 13, 402-405
76. D. Chen, Z. Wang, J. Li, Z. Yang, L. Lin, X. Liu, X. Feng, Chem. Eur. J. 2011, 17, 5226-5229.
77. For a review on hetero-Diels-Alder reactions of ketones, see:, K. A. Jørgensen, Eur. J. Org. Chem. 2004, 2093-2102.
78. J. Thorhauge, M. Johannsen, K. A. Jørgensen, Angew. Chem. Int. Ed. 1998, 37, 2404-2406
79. Angew. Chem. 1998, 110, 2543-2546
80. D. A. Evans, J. S. Johnson, E. J. Olhava, J. Am. Chem. Soc. 2000, 122, 1635-1649
81. H. Audrain, J. Thorhauge, R. G. Hazell, K. A. Jørgensen, J. Org. Chem. 2000, 65, 4487-4497
82. Y. Shin, C.-E. Yeom, M. Kim, B. Kim, Synlett 2008, 89-93
83. Y. Zhu, M. Xie, S. Dong, X. Zhao, L. Lin, X. Liu, X. Feng, Chem. Eur. J. 2011, 17, 8202-8208
84. Y. Zhou, Y. Zhu, L. Lin, Y. Zhang, J. Zheng, X. Liu, X. Feng, Chem. Eur. J. 2014, 20, 16753-16758.
85. E. J. Corey, N. Imai, H. Y. Zhang, J. Am. Chem. Soc. 1991, 113, 728-729
86. D. A. Evans, S. J. Miller, T. Lectka, J. Am. Chem. Soc. 1993, 115, 6460-6461
87. K. V. Gothelf, K. A. Jorgensen, J. Org. Chem. 1995, 60, 6847-6851
88. D. A. Evans, J. A. Murry, P. von Matt, R. D. Norcross, S. J. Miller, Angew. Chem. Int. Ed. Engl. 1995, 34, 798-800
89. Angew. Chem. 1995, 107, 864-867
90. A. K. Ghosh, P. Mathivanan, J. Cappiello, Tetrahedron Lett. 1996, 37, 3815-3818
91. I. Sagasser, G. Helmchen, Tetrahedron Lett. 1998, 39, 261-264
92. S. Otto, G. Boccaletti, J. B. F. N. Engberts, J. Am. Chem. Soc. 1998, 120, 4238-4239
93. D. A. Evans, D. M. Barnes, J. S. Johnson, T. Lectka, P. von Matt, S. J. Miller, J. A. Murry, R. D. Norcross, E. A. Shaughnessy, K. R. Campos, J. Am. Chem. Soc. 1999, 121, 7582-7594
94. M. P. Sibi, L. M. Stanley, X. Nie, L. Venkatraman, M. Liu, C. P. Jasperse, J. Am. Chem. Soc. 2007, 129, 395-405
95. A. J. Boersma, J. E. Klijn, B. L. Feringa, G. Roelfes, J. Am. Chem. Soc. 2008, 130, 11783-11790
96. C. Wang, G. Jia, J. Zhou, Y. Li, Y. Liu, S. Lu, C. Li, Angew. Chem. Int. Ed. 2012, 51, 9352-9355
97. Angew. Chem. 2012, 124, 9486-9489
98. A. J. Boersma, B. de Bruin, B. L. Feringa, G. Roelfes, Chem. Commun. 2012, 48, 2394-2396.
99. For the conjugate addition to α,β-unsaturated 2-acyl benzimidazoles, see:, M. Yoshida, H. Ohmiya, M. Sawamura, J. Am. Chem. Soc. 2012, 134, 11896-11899. See also ref. [15b].
100. A. Dondoni, L. Kniezo, M. Martinkova, J. Chem. Soc. Chem. Commun 1994, 1963-1964
101. A. Dondoni, A. Marra, A. Boscarato, Chem. Eur. J. 1999, 5, 3562-3572
102. M. Sani, G. Fossati, F. Huguenot, M. Zanda, Angew. Chem. Int. Ed. 2007, 46, 3526-3529
103. Angew. Chem. 2007, 119, 3596-3599
104. P. S. Shankar, M. Sani, G. Terraneo, M. Zanda, Synlett 2009, 1341-1345
105. P. Kwiatkowski, A. Cholewiak, A. Kasztelan, Org. Lett. 2014, 16, 5930-5933. See also ref. [15b].
106. M. P. Sibi, Y. H. Yang, Synlett 2008, 83-88
107. P. K. Singh, V. K. Singh, Org. Lett. 2008, 10, 4121-4124
108. N. Molleti, N. K. Rana, V. K. Singh, Org. Lett. 2012, 14, 4322-4325
109. S. Lin, Y. Wei, F. Liang, Chem. Commun. 2012, 48, 9879-9881
110. G. Blay, C. Incerti, M. C. Muñoz, J. R. Pedro, Eur. J. Org. Chem. 2013, 1696-1705
111. X.-Q. Hao, J.-J. Huang, T. Wang, J. Lv, J.-F. Gong, M.-P. Song, J. Org. Chem. 2014, 79, 9512-9530.
112. S. Kobayashi, C. Ogawa, M. Kawamura, M. Sugiura, Synlett 2001, 0983-0985
113. D. J. Guerin, S. J. Miller, J. Am. Chem. Soc. 2002, 124, 2134-2136
114. A. W. Hird, A. H. Hoveyda, Angew. Chem. Int. Ed. 2003, 42, 1276-1279
115. Angew. Chem. 2003, 115, 1314-1317
116. Y. Hoashi, T. Okino, Y. Takemoto, Angew. Chem. Int. Ed. 2005, 44, 4032-4035
117. Angew. Chem. 2005, 117, 4100-4103
118. C. Palomo, R. Pazos, M. Oiarbide, J. M. García, Adv. Synth. Catal. 2006, 348, 1161-1164
119. A. M. M. Abe, S. J. K. Sauerland, A. M. P. Koskinen, J. Org. Chem. 2007, 72, 5411-5413
120. L. Fadini, A. Togni, Tetrahedron: Asymmetry 2008, 19, 2555-2562
121. M. P. Sibi, Y.-H. Yang, S. Lee, Org. Lett. 2008, 10, 5349-5352
122. Y. Liu, B. Sun, B. Wang, M. Wakem, L. Deng, J. Am. Chem. Soc. 2009, 131, 418-419
123. S. Murarka, I. Deb, C. Zhang, D. Seidel, J. Am. Chem. Soc. 2009, 131, 13226-13227
124. Y. Huang, E. Tokunaga, S. Suzuki, M. Shiro, N. Shibata, Org. Lett. 2010, 12, 1136-1138
125. S. Harada, T. Morikawa, A. Nishida, Org. Lett. 2013, 15, 5314-5317
126. L. Wen, L. Yin, Q. Shen, L. Lu, Acs Catal. 2013, 3, 502-506
127. Y. Sakaguchi, N. Kurono, K. Yamauchi, T. Ohkuma, Org. Lett. 2014, 16, 808-811. See also ref. [15b].
128. For the conjugate addition to α,β-unsaturated N-acylthiazolidinethiones, see:, D. A. Evans, R. J. Thomson, F. Franco, J. Am. Chem. Soc. 2005, 127, 10816-10817. See also ref. [15b].
129. C. Kashima, K. Takahashi, I. Fukuchi, K. Fukusaka, Heterocycles 1997, 44, 289-304
130. M. P. Sibi, J. J. Shay, M. Liu, C. P. Jasperse, J. Am. Chem. Soc. 1998, 120, 6615-6616
131. C. Kashima, K. Fukusaka, K. Takahashi, Y. Yokoyama, J. Org. Chem. 1999, 64, 1108-1114
132. K. Itoh, S. Kanemasa, J. Am. Chem. Soc. 2002, 124, 13394-13395
133. C. Kashima, Y. Miwa, S. Shibata, H. Nakazono, J. Heterocycl. Chem. 2003, 40, 681-688
134. K. Itoh, Y. Oderaotoshi, S. Kanemasa, Tetrahedron: Asymmetry 2003, 14, 635-639
135. K. Itoh, M. Hasegawa, J. Tanaka, S. Kanemasa, Org. Lett. 2005, 7, 979-981
136. H. Yanagita, K. Kodama, S. Kanemasa, Tetrahedron Lett. 2006, 47, 9353-9357
137. K. Ishihara, M. Fushimi, Org. Lett. 2006, 8, 1921-1924
138. M. P. Sibi, K. Itoh, J. Am. Chem. Soc. 2007, 129, 8064-8065
139. F. Ono, M. Hasegawa, S. Kanemasa, J. Tanaka, Tetrahedron Lett. 2008, 49, 5105-5107
140. M. Hasegawa, F. Ono, S. Kanemasa, Tetrahedron Lett. 2008, 49, 5220-5223
141. X.-Q. Dong, X. Fang, H.-Y. Tao, X. Zhou, C.-J. Wang, Chem. Commun. 2012, 48, 7238
142. X.-Q. Dong, X. Fang, H.-Y. Tao, X. Zhou, C.-J. Wang, Adv. Synth. Catal. 2012, 354, 1141-1147
143. J. Zhang, X. Liu, R. Wang, Chem. Eur. J. 2014, 20, 4911-4915. See also ref. [15b].
144. H. Jiang, M. W. Paixão, D. Monge, K. A. Jørgensen, J. Am. Chem. Soc. 2010, 132, 2775-2783
145. D. A. Evans, K. A. Scheidt, K. R. Fandrick, H. W. Lam, J. Wu, J. Am. Chem. Soc. 2003, 125, 10780-10781
146. Y. K. Kang, K. H. Suh, D. Y. Kim, Synlett 2011, 1125-1128
147. N. Takenaka, J. P. Abell, H. Yamamoto, J. Am. Chem. Soc. 2007, 129, 742-743
148. P. Bachu, T. Akiyama, Chem. Commun. 2010, 46, 4112-4114. See also ref. [15b].
149. K. B. Jensen, J. Thorhauge, R. G. Hazell, K. A. Jørgensen, Angew. Chem. Int. Ed. 2001, 40, 160-163
150. Angew. Chem. 2001, 113, 164-167
151. K. A. Jørgensen, Synthesis 2003, 1117-1125
152. M. Rueping, B. J. Nachtsheim, S. A. Moreth, M. Bolte, Angew. Chem. Int. Ed. 2008, 47, 593-596
153. Angew. Chem. 2008, 120, 603-606
154. S.-L. Zhao, C.-W. Zheng, H.-F. Wang, G. Zhao, Adv. Synth. Catal. 2009, 351, 2811-2816
155. Y. Liu, D. Shang, X. Zhou, Y. Zhu, L. Lin, X. Liu, X. Feng, Org. Lett. 2010, 12, 180-183
156. J. Lv, X. Li, L. Zhong, S. Luo, J.-P. Cheng, Org. Lett. 2010, 12, 1096-1099
157. L. Zhou, L. Lin, W. Wang, J. Ji, X. Liu, X. Feng, Chem. Commun. 2010, 46, 3601-3603
158. B. Yang, F. Xie, H. Yu, K. Shen, Z. Ma, W. Zhang, Tetrahedron 2011, 67, 6197-6201
159. J. Lv, L. Zhang, Y. Zhou, Z. Nie, S. Luo, J.-P. Cheng, Angew. Chem. Int. Ed. 2011, 50, 6610-6614
160. Angew. Chem. 2011, 123, 6740-6744
161. L. Gremaud, A. Alexakis, Angew. Chem. Int. Ed. 2012, 51, 794-797
162. Angew. Chem. 2012, 124, 818-821
163. L. Liu, H. Ma, Y. Xiao, F. Du, Z. Qin, N. Li, B. Fu, Chem. Commun. 2012, 48, 9281-9283
164. J. Duan, F. Cao, X. Wang, C. Ma, Chem. Commun. 2013, 49, 1124-1126
165. Y. Zhang, X. Liu, X. Zhao, J. Zhang, L. Zhou, L. Lin, X. Feng, Chem. Commun. 2013, 49, 11311-11313
166. H.-G. Cheng, L.-Q. Lu, T. Wang, Q.-Q. Yang, X.-P. Liu, Y. Li, Q.-H. Deng, J.-R. Chen, W.-J. Xiao, Angew. Chem. Int. Ed. 2013, 52, 3250-3254
167. Angew. Chem. 2013, 125, 3332-3336
168. S. Zhang, K. Xu, F. Guo, Y. Hu, Z. Zha, Z. Wang, Chem. Eur. J. 2014, 20, 979-982
169. Q. Wang, J. Gong, Y. Liu, Y. Wang, Z. Zhou, Tetrahedron 2014, 70, 8168-8173
170. S.-J. Jia, D.-M. Du, Tetrahedron: Asymmetry 2014, 25, 980-988
171. J. Wang, B. Wang, P. Cao, J. Liao, Tetrahedron Lett. 2014, 55, 3450-3453
172. E. Sánchez-Larios, K. Thai, F. Bilodeau, M. Gravel, Org. Lett. 2011, 13, 4942-4945
173. A. Lefranc, L. Gremaud, A. Alexakis, Org. Lett. 2014, 16, 5242-5245
174. J. Wang, M. Wang, P. Cao, L. Jiang, G. Chen, J. Liao, Angew. Chem. Int. Ed. 2014, 53, 6673-6677
175. Angew. Chem. 2014, 126, 6791-6795
176. Y. Zhang, N. Yang, X. Liu, J. Guo, X. Zhang, L. Lin, C. Hu, X. Feng, Chem. Commun. 2015, 51, 8432-8435.
177. R. Shintani, T. Kimura, T. Hayashi, Chem. Commun. 2005, 3213-3214
178. J. R. de Alaniz, M. S. Kerr, J. L. Moore, T. Rovis, J. Org. Chem. 2008, 73, 2033-2040
179. L. Li, J.-Y. Guo, X.-G. Liu, S. Chen, Y. Wang, B. Tan, X.-Y. Liu, Org. Lett. 2014, 16, 6032-6035.
180. S. Ohta, S. Hayakawa, K. Nishimura, M. Okamoto, Chem. Pharm. Bull. 1987, 35, 1058-1069
181. A. Miyashita, Y. Suzuki, I. Nagasaki, C. Ishiguro, K. Iwamoto, T. Higashino, Chem. Pharm. Bull. 1997, 45, 1254-1258.