Synthesis of Pyrrolizidines and Indolizidines by the Intramolecular Cycloaddition of Azides with Electron-Rich 1,3-Dienes. A Synthetic Equivalent of a Nitrene-Diene Cycloaddition

Journal of Organic Chemistry

Volumn 55, Issue 22, 1990, Pages 5719-5738

  Pearson, William H ^a   Lin, Ko Chung ^a   Poon, Yam Foo ^a   Schkeryantz, Jeffrey M ^a   Williams, John P ^a   Bergmeier, Stephen C ^a   Degan, Samir ^a  

^a UNIVERSITY OF MICHIGAN   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0000330327     PISSN: 00223263     EISSN: 15206904     Source Type: Journal    
DOI: 10.1021/jo00309a016     Document Type: Article

References (166)

1. Pyrrolizidine alkaloids: (a) Numata, A.; Ibuka, T. In The Alkaloids; Brossi, A., Ed.; Academic Press: San Diego, 1987; Vol. 31, Chapter 6, pp 193–315.
2. Ikeda, M.; Sato, T.; Ishibashi, H. Heterocycles 1988, 27, 1465–1487.
3. Robins, D. J. Nat. Prod. Rep. 1989, 6, 221–230.
4. Indolizidine alkaloids: (a) Daly, J. W.; Spande, T. F. In Alkaloids: Chemical and Biological Perspectives; Pelletier, S. W., Ed.; Wiley: New York, 1986; Vol. 4.
5. Grundon, M. F. Nat. Prod. Rep. 1989, 6, 523–536.
6. Elbein, A. D.; Molyneux, R. J. In Alkaloids: Chemical and Biological Perspectives; Pelletier, S. W., Ed.; Wiley: New York, 1987; Vol. 5, Chapter 1. pp 1–54.
7. For polycyclic alkaloids having such a subfeature, see for example: Martin, S. F. In The Alkaloids; Brossi, A., Ed.; Academic Press: San Diego, 1986; Vol. 30. Chapter 3, pp 251–376.
8. Other formal [4 + 1] approaches to pyrrolidines and 3-pyrrolines have been reported: (a) Keck, G. E.; Nickell, D. G. J. Am. Chem. Soc. 1980, 102, 3632.
9. Barluenga, J.; Perez-Prieto, J.; Asensio, G. J. Chem. Soc., Chem. Commun. 1982, 1181.
10. Forrest, A. K.; Schmidt, R. R. Tetrahedron Lett. 1984, 25, 1769.
11. Fugami, K.; Morizawa, Y.; Oshima, K.; Nozaki, H. Tetrahedron Lett. 1985, 26, 857.
12. Gajda, T.; Zwierzak, A. Liebigs Ann. Chem. 1986, 992–1002.
13. Backvall, J. E.; Renko, Z. D.; Bystrom, S. E. Tetrahedron Lett. 1987, 28, 4199–4202.
14. Miura, K.; Fugami, K.; Oshima, K.; Utimoto, K. Tetrahedron Lett. 1988, 29, 1543–1546.
15. Burkholder, T. P.; Fuchs, P. L. J. Am. Chem Soc. 1988, 110, 2341–2342.
16. Padwa, A.; Norman, B. H. Tetrahedron Lett. 1988, 29, 3041–3044.
17. A nonconcerted reaction of triplet cyanonitrene with cyclo-octatetraene produces a 3-pyrroline by a [4 + 1] cyclization without the intermediacy of a vinylaziridine: (a) Anastassiou, A. G. J. Am. Chem. Soc. 1965, 87, 5512.
18. Anastassiou, A. G. J. Am. Chem. Soc. 1968, 90, 1527.
19. Anastassiou, A. G.; Cellura, R. P.; Ciganek, E. Tetrahedron Lett. 1970, 5267–5270.
20. See also reference 13 for a potentially direct nitrene/diene cyclization. Concerted 1,4-additions of carbenes to dienes to give cyclopentenes without the intermediacy of a vinylcyclopropane have been found: (d) Le, N. A.; Jones, M., Jr.; Bickelhaupt, F.; de Wolf, W. H. J. Am. Chem. Soc. 1989, 111, 8491–8493 and references cited therein.
21. Kraakman, P. A.; de Wolf, W. H.; Bickelhaupt, F. J. Am. Chem. Soc. 1989, 111, 8534–8535.
22. Evanseck, J. D.; Mareda, J.; Houk, K. N. J. Am. Chem. Soc. 1990, 112, 73–80.
23. Lwowski, W., Ed. Nitrenes; Wiley: New York, 1970.
24. Nagata, W. Lect. Heterocycl. Chem. 1972, 1, 29.
25. Lwowski, W. In Reactive Intermediates; Jones, M., Moss, R. A., Eds.; Wiley: New York, 1981; Chapter 8.
26. Deyrup, J. A. In Heterocyclic Compounds; Hassner, A., Ed.; Wiley: New York, 1983; Vol. 42, Part 1, Chapter 1, pp. 1–214.
27. Kyba, E. P. In Azides and Nitrenes-Reactivity and Utility; Scriven, E. F. V., Ed.; Academic Press: New York, 1984; Chapter 1.
28. Kametani, T.; Honda, T. Adv. Heterocycl. Chem. 1986, 39, 182–236.
29. Atkinson, R. S.; Rees, C. W. J. Chem. Soc., Chem. Commun. 1967, 1232.
30. Atkinson, R. S.; Rees, C. W. J. Chem. Soc. C 1969, 778–782.
31. Mishra, A.; Rice, S. N.; Lwowski, W. J. Org. Chem. 1968, 33, 481–486.
32. Hoesch, L.; Dreiding, A. S. Chimia 1972, 26, 629.
33. See also: Nelsen, S. F.; Blackstock, S. C.; Steffek, D. J.; Cunkle, G. T.; Kurtzweil, M. L. J. Am. Chem. Soc. 1988, 110, 6149–6153.
34. Portions of this work were communicated In: (a) Pearson, W. H. Tetrahedron Lett. 1985, 26, 3527–3530.
35. Pearson, W. H.; Celebuski, J. E.; Poon, Y.-F.; Dixon, B. R.; Glans, J. H. Tetrahedron Lett. 1986, 27, 6301–6304.
36. For an approach to gephyrotoxin using this methodology, see: (c) Pearson, W. H.; Poon, Y.-F. Tetrahedron Lett. 1989, 30, 6661–6664. For related work, see ref 18.
37. Reviews: (a) Trost, B. M. Top. Curr. Chem. 1986, 133, 3.
38. Salaun, J. R. Y. Top. Curr. Chem. 1988, 144, 1–71.
39. Goldschmidt, Z.; Crammer, B. Chem. Soc. Rev. 1988, 17, 229.
40. Wong, H. N. C.; Hon, M.-Y.; Tse, C.-W.; Yip, Y.-C.; Tanko, J.; Hudlicky, T. Chem. Rev. 1989, 89, 165–198.
41. Attempted nitrene generation from azides such as those in Scheme I by photolysis, or from the corresponding amines by oxidation led to complex mixtures in our hands.
42. Naruta, Y.; Arita, Y.; Nagai, N.; Uno, H.; Maruyama, K. Chem. Lett. 1982, 1859.
43. Naruta, Y.; Nagai, N.; Maruyama, K. Chem. Lett. 1983, 1383.
44. Naruta, Y.; Nagai, N.; Maruyama, K. Heterocycles 1984, 21, 410.
45. Naruta, Y.; Nagai, N.; Arita, Y.; Maruyama, K. J. Org. Chem. 1987, 52, 3956.
46. General references on azide-alkene cycloadditions: (a) Scheiner, P. In Selective Organic Transformations; Thyagarajan, B. S., Ed.; Wiley: New York, 1970.
47. Sheradsky, T. In The Chemistry of the Azido Group; Patai, S., Ed.; Wiley: New York, 1971; Chapter 6.
48. Finley, K.-T. In The Chemistry of Heterocyclic Compounds; Montgomery, J. A., Ed.; Wiley: New York, 1980; Vol. 39.
49. Lwowski, W. In 1,3-Dipolar Cycloaddition Chemistry; Padwa, A., Ed.; Wiley-Interscience: New York, 1984; Vol. 1, Chapter 5, pp 559–651.
50. Kadaba, P. K.; Stanovnik, B.; Tisler, M. Adv. Heterocycl. Chem. 1984, 37, 217–361.
51. Scriven, E. F. V.; Turnbull, K. Chem. Rev. 1988, 88, 297–368.
52. Intramolecular azide-alkene cycloadditions. Reviews: (a) Padwa, A. Angew. Chem., Int. Ed. Engl. 1976, 15, 123.
53. Oppolzer, W. Angew. Chem., Int. Ed. Engl. 1977, 16, 10.
54. Padwa, A. In 1,3-Dipolar Cyclo-addition Chemistry; Padwa, A., Ed.; Wiley: New York, 1984; Vol. 2, Chapter 12, pp 277–406.
55. Tsuge, O.; Hatta, T.; Hisano, T. In The Chemistry of Double-Bonded Functional Groups; Patai, S., Ed.; Wiley: New York, 1989; Vol. 1, Chapter 7, pp 344–475.
56. Selected additional intramolecular examples: (e) Logothetis, A. L. J. Am. Chem. Soc. 1965, 87, 749.
57. Corey, E. J.; Balanson, R. D. Heterocycles 1976, 5, 445.
58. Bertrand, M.; Dulcere, J. P.; Santell, M. Tetrahedron Lett. 1977, 1783.
59. Schultz, A. G.; Ravichandran, R. J. Org. Chem. 1980, 45, 5008.
60. Sundberg, R. J.; Pearce, B. C. J. Org. Chem. 1982, 47, 725.
61. Kozikowski, A. P.; Greco, M. N. Tetrahedron Lett. 1982, 23, 2005.
62. Schultz, A. G.; McMahon, W. G. J. Org. Chem. 1984, 49, 1676–1678.
63. Kozikowski, A. P.; Greco, M. N. J. Org. Chem. 1984, 49, 2310.
64. Pearson, M. J.; Tyler, J. W. J. Chem. Soc., Perkin Trans. 1 1985, 28, 1927.
65. Sha, C.-K.; Ouyang, S.-L.; Hsieh, D.-Y.; Chang, R.-C.; Chang, S.-C. J. Org. Chem. 1986, 51, 1490–1494.
66. Buchanan, J. G.; Edgar, A. R.; Hewitt, B. D. J. Chem. Soc., Perkin Trans. 1 1987, 2371–2376.
67. Murthy, K. S. K.; Hassner, A. Tetrahedron Lett. 1987, 28, 97–100.
68. Tsai, C.-Y.; Sha, C.-K. Tetrahedron Lett. 1987, 28, 1419–1420 and earlier references.
69. Hassner, A.; Amarasekara, A. S.; Andisik, D. J. Org. Chem. 1988, 53, 27–30.
70. Taber, D. F.; Deker, P. B.; Fales, H. M.; Jones, T. H.; Lloyd, H. A. J. Org. Chem. 1988, 53, 2968–2971.
71. Vogel, C.; Delavier, P. Tetrahedron Lett. 1989, 30, 1789–1792.
72. Fukuyama, T.; Yang, L. J. Am. Chem. Soc. 1989, 111, 8303–8304 and earlier references therein.
73. Buchanan, J. G.; Edgar, A. R.; Hewitt, B. D.; Jigajinni, B. B.; Singh, G.; Wightman, R. H. In Trends in Synthetic Carbohydrate Chemistry; Horton, D.; Hawkins, L. D., McGarvey, G. J., Eds.; American Chemical Society: Washington, D.C., 1989; Chapter 6, pp 107–116.
74. Scheiner, P. Tetrahedron 1968, 24, 349–356.
75. Scheiner, P. Tetrahedron 1968, 24, 2757–2765.
76. Scheiner, P. J. Org. Chem. 1967, 32, 2628.
77. Schultz, A. G.; Dittami, J. P.; Myong, S. O.; Sha, C.-K. J. Am. Chem. Soc, 1983, 105, 3273.
78. Schultz, A. G.; Staib, R. R.; Eng, K. K. J. Org. Chem. 1987, 52, 2968.
79. Schultz, A. G. In Advances in Cyclo-addition; Curran, D. P., Ed.; JAI Press: Greenwich, CT, 1988; Vol. 1, pp 53–85.
80. For work related to our early studies,10asee: (a) Hudlicky, T.; Frazier, J. O.; Kwart, L. D. Tetrahedron Lett. 1985, 26, 3523–3526.
81. See also: (b) Hudlicky, T.; Frazier, J. O.; Seoane, G.; Tiedje, M.; Seoane, A.; Kwart, L. D.; Beal, C. J. Am. Chem. Soc. 1986, 108, 3755–3762.
82. Hudlicky, T.; Sinai-Zingde, G.; Seoane, G. Synth. Commun. 1987, 17, 1155.
83. Hudlicky, T.; Seoane, G. Lovelace, T. C. J. Org. Chem. 1988, 53, 2094–2099.
84. Scheiner, P. J. Org. Chem. 1965, 30, 7.
85. Scheiner, P. J. Am. Chem. Soc. 1966, 88, 4759.
86. Stark, B. P.; Duke, A. J. Extrusion Reactions; Pergamon Press: New York, 1967.
87. Scheiner, P. J. Am. Chem. Soc. 1968, 90, 988–992.
88. McDaniel, R. S.; Oehlschlager, A. C. Tetrahedron 1969, 25, 1381. See also ref 14e.
89. For related ionic method for vinylaziridine rearrangement, see: (a) Muxfeldt, H.; Schneider, R. S.; Mooberry, J. B. J. Am. Chem. Soc. 1966, 88, 3670.
90. Hortmann, A. G.; Koo, J. J. Org. Chem. 1974, 39, 3781.
91. Expert, J.; Gelas-Mialhe, Y.; Vessiere, R. J. Heterocycl. Chem. 1985, 22, 1285–1289.
92. For 1,5-homodienyl shift in vinylaziridines: (a) Reference 6d. (b) Sauleau, A.; Sauleau, A.; Bourget, H.; Huet, J. C. R. Acad. Sci. Paris, Ser. C 1974, 279, 473.
93. Borel, D.; Gelas-Mialhe, Y.; Vessiere, R. Can. J. Chem. 1976, 54, 1582, 1590.
94. Sauleau, A.; Sauleau, A.; Huet, J. Bull. Soc. Chim. Fr. 1978, 97.
95. Hassner, A.; D’Costa, R.; McPhail, A. T.; Butler, W. Tetrahedron Lett. 1981, 22, 3691.
96. Hassner, A.; Chau, W. Tetrahedron Lett. 1982, 23, 1989.
97. Eberbach, W.; Carre, J. C. Chem. Ber. 1983, 116, 563.
98. For 1,5-homodienyl shift in vinylcyclopropanes: (h) Daub, J. P.; Berson, J. A. Tetrahedron Lett. 1984, 25, 4463 and references therein.
99. Loncharich, R. J.; Houck, K. N. J. Am. Chem. Soc. 1988, 110, 2089 and references therein.
100. Gajewski, J. J.; Squicciarini, M. P. J. Am. Chem. Soc. 1989, 111, 6717–6728 and references therein.
101. Borel, D.; Gelas-Mialhe, Y.; Vessiere, R. Can. J. Chem. 1976, 54, 1590.
102. Pommelet, J. C.; Chuche, J. Can. J. Chem. 1976, 54, 1571.
103. Heteroatoms at a similar position have been shown to increase the rate of the vinylcyclopropane rearrangement,11 and the cyclopropylimine rearrangement.24 See also: Danheiser, R. L.; Bronson, J. J.; Okano, K. J. Am. Chem. Soc. 1985, 107, 4579–4581 and references therein.
104. Wasserman, H. H.; Dion, R. P. Tetrahedron Lett. 1982, 23, 1413.
105. Wasserman, H. H.; Dion, R. P.; Fukuyama, J. Tetrahedron 1989, 45, 3203–3216.
106. Although halogenated solvents are not the first choice for reactions involving amines (such as 13) at elevated temperatures, chloroform was empirically found to give the cleanest reaction and highest yields of 12 for the sulfur-substitued dienes. For a leading reference on the reaction of amines with halogenated solvents, see: Mills, J. E.; Maryanoff, C. A.; McComsey, D. F.; Stanzione, R. C.; Scott, L. J. Org. Chem. 1987, 52, 1857–1859.
107. Huisgen, R. In 1,3-Dipolar Cycloaddition Chemistry; Padwa, A., Ed.; Wiley-Interscience: New York, 1984; Vol. 1, Chapter 1, pp 1–176.
108. Fleming, I. Frontier Orbitals and Organic Chemical Reactions; Wiley: new York, 1976.
109. Kahn, S. D.; Pau, C. F.; Overman, L. E.; Hehre, W. J. J. Am. Chem. Soc. 1986, 108, 7381–7396.
110. See refs 39, 40, and Chou, S.-S. P.; Liou, S.-Y.; Tsai, C.-Y.; Wang, A. -J. J. Org. Chem. 1987, 52, 4468–4471.
111. Uhle, F. C. J. Org. Chem. 1967, 32, 1596.
112. Scheiner, P. J. Org. Chem. 1967, 32, 2022–2023.
113. Ito, M. M.; Nomura, Y.; Takeuchi, Y.; Tomada, S. Heterocycles 1984, 21, 627.
114. Kitane, S.; Berrada, M.; Vebrel, J.; Lande, B. Bull. Chem. Soc. Belg. 1985, 94, 163–164.
115. Chabala, J. C.; Christensen, B. G.; Ratcliffe, R. W.; Woods, M. F. Tetrahedron Lett. 1985, 26, 5407–5410.
116. Goldsmith, D.; Soria, J. J. Tetrahedron Lett. 1986, 27, 4701–4704.
117. DiNunno, L.; Scilimati, A. Tetrahedron 1986, 42, 3913.
118. Mohrle, H.; Dwuletzi, H. Chem. Ber. 1986, 119, 3591–3599.
119. Cipollone, A.; Loreto, M. A.; Pellacani, L.; Tardella, P. A. J. Org. Chem. 1987, 52, 2584–2586.
120. Kheruze, Y. I.; Galishev, V. A.; Petrov, A. A. J. Org. Chem. USSR 1988, 24, 852–856.
121. Nugent, W. A.; Haymore, B. L. Coord. Chem. Rev. 1980, 31, 123.
122. Among the other transition metal catalysts tried were: PdCl2, NiCl2, Rh/Al203, RhCl(PPh3)3, Rh(II) acetate, [(COD)RhCl]2, RuCl2-(PPh3)3, Ag20, and RhCl3-3H20.
123. Increasing evidence suggests that such closures are reasonable: (a) Duboudin, J.-G.; Jousseaume, B. Synth. Commun. 1979, 9, 53–56.
124. Trost, B. M.; Bonk, P. J. J. Am. Chem. Soc. 1985, 107, 1778–1781.
125. Knochel, P. A.; Normant, J. F. Tetrahedron Lett. 1985, 26, 4455–4458.
126. Tanaka, K.; Yoda, H.; Kaji, A. Tetrahedron Lett. 1985, 26, 4747–4750, 4751–4754.
127. Beak, P.; Wilson, K. D. J. Org. Chem. 1986, 51, 4627–4639 and references therein.
128. Tarnchompoo, B.; Thebtaranonth, C.; Theb-tarononth, Y. Tetrahedron Lett. 1987, 28, 6675–6678.
129. Padwa, A. Yeske, P. E. J. am. Chem. Soc. 1988, 110, 1617–1618.
130. Padwa, A.; Norman, B. H. Tetrahedron Lett. 1988, 29, 3041–3044.
131. Beak, P.; Burg, D. A. J. Org. Chem. 1989, 54, 1647–1654.
132. Annunziana, R.; Cinquini, M.; Cozzi, F.; Raimondi, L. Gazz. Chim. Ital. 1989, 119, 253–269.
133. Curran, D. P.; Gothe, S. A. Tetrahedron 1988, 44, 3945–3952 and earlier references.
134. Confalone, P. N. Org. React. 1988, 36, 1.
135. Pearson, W. H. In Studies in Natural Products Chemistry: Volume 1, Stereoselective Synthesis (Part A), Rahman. A., Ed.; Elsevier: New York, 1988; pp 323–328.
136. Marshall, J. A.; Shearer, B. G.; Crooks, S. L. J. Org. Chem. 1987, 52, 1236–1245. Compound 59 was made in a fashion similar to the preparation of 53, except iodine was used to quench the vinyl alanate rather that PhSCl.
137. Prepared using the chemistry of McDougal: McDougal, P. G.; Rico, J. G. J. Org. Chem. 1987, 52, 4817–4819.
138. l-Lithio-2,3-bis(methoxymethoxy)-1,3-butadiene was added to 4-azidobutanal and the resultant alcohol was protected with MOM-Cl/iPr2NEt to provide 61. We thank Professor McDougal for providing the procedure for generating the metalated butadiene.
139. Review on allylic 1,3-strain in controlling stereochemistry: Hoffmann, R. W. Chem. Rev. 1989, 89, 1841–1860.
140. Roush, W. R.; Brown, B. B.; Drozda, S. E. Tetrahedron Lett. 1988, 29, 3541–3544.
141. Roush, W. R.; Riva, R. J. Org. Chem. 1988, 53, 710.
142. Boeckman, R. K., Jr.; Barta, T. E. J. Org. Chem. 1985, 50, 3421.
143. McDougal, P. G.; Rico, J. G.; VanDerveer, D. J. Org. Chem. 1986, 51, 4492–4494.
144. Intermolecular examples with dienes bearing allylic ethers: (e) Tripathy, R.; Franck, R. W.; Onan, K. D. J. Am. Chem. Soc. 1988, 110, 3257–3262 and references therein.
145. Reitz, A. B.; Jordon, A. D., Jr.; Maryanoff, B. E. J. Org. Chem. 1987, 52, 4800–4802.
146. Gupta, R. C.; Raynor, C. M.; Stoodley, R. J.; Slawin, A. M. Z.; Williams, D. J. J. Chem. Soc., Perkin Trans. 1 1988, 1773–1785.
147. Pearson, W. H.; Lin, K.-C.; Poon, Y.-F. J. Org. Chem. 1989, 54, 5814–5819.
148. We had originally used the titanium based method reported by Yamamoto, but have found that the allyl borane 73 is more convenient and also provides access to either diene geometry. The titanium analogue produces the E geometry: Furuta, K.; Ikeda, Y.; Meguriya, N.; Ikeda, N.; Yamamoto, H. Bull. Chem. Soc. Jpn. 1984, 57, 2781–2790.
149. Murai, A.; Abiko, A.; Shimada, N.; Masamune, T. Tetrahedron Lett. 1984, 25, 4951.
150. Oppolzer, W.; Snowden, R. L.; Simmons, D. P. Helv. Chim. Acta 1981, 64, 2002.
151. Oppolzer has reported the synthesis of silyloxy dienes from 104. We have extended this methodology to 2-(ethoxyethoxy) dienes from 105.
152. Schkeryantz, J., unpublished results.
153. Okazoe, T.; Takai, K.; Oshima, K.; Utimoto, K. J. Org. Chem. 1987, 52, 4412.
154. Still, W. C.; Kahn, M.; Mitra, A. J. Org. Chem. 1978, 43, 2923–2925.
155. Pirrung, M. C.; Webster, N, J. G. J. Org. Chem. 1987, 52, 3603.
156. Danishefsky, S. J.; Pearson, W. H. J. Org. Chem. 1983, 48, 3865.
157. McDougal, P. G.; Rico, J. G.; Oh, Y.-I.; Condon, B. D. J. Org. Chem. 1986, 51, 3388.
158. Brandsma, L.; Verkruijsse, H. Synthesis of Acetylenes, Allenes and Cumulenes; Elsevier; new York 1981.
159. Vasella, A.; Bernet, A. Helv. Chim. Acta 1979, 62, 1990.
160. Lab, B.; Pramanik, B. N.; Monnhas, M. S.; Bose, A. K. Tetrahe dron Lett. 1977, 23, 1977.
161. Brandsma, L.; Verkruijsse, H. Preparative Polar Organometallic Chemistry 1; Springer-Verlag: New York, 1987.
162. Harpp, D. N.; Mathiaparanam, P. J. Org. Chem. 1972, 37, 1367.
163. Denney, D. B.; Ross, S. T. J. Org. Chem. 1962, 27, 998.
164. Although this compound is known,54a we prepared it by an alternative procedure. l-(Trimethylsilyl)prop-2-en-l-ol54bwas acylated with N,N-diisopropylcarbamoyl chloride in refluxing toluene containing N,N- diisopropylethylamine (67% yield after 14 h). (a) Hoppe, D.; Hanko, R.; Bronneke, A.; Lichtenberg, F.; von Hulsen, E. Chem. Ber. 1985, 118, 2822.
165. Danheiser, R. L.; Fink, D. M.; Okano, K.; Tsai, Y.-M. Szczepanski, S. W. Org. Synth. 1987, 66, 14.
166. Normant, J. F.; Villieras, J.; Bacquet, C. Bull. Soc. Chim. Fr. 1975, 1797.