E. Vogel, Angew. Chem. Int. Ed. Engl, vol.2, pp.1-11, 1963.

M. Rey and A. S. Dreiding, Helv. Chim. Acta, vol.48, 1965.

S. R. Rhoads and R. D. Cockroft, J. Am. Chem. Soc, vol.91, pp.2815-2816, 1969.

B. Hofmann and H. Reißig, Chem. Ber, vol.127, pp.2327-2335, 1993.

R. K. Boeckman, M. D. Shair, J. R. Vargas, and L. A. Stolz, J. Org. Chem, vol.58, pp.1295-1297, 1993.

S. Yamaguchi, A. Arisawa, N. Katoh, K. Hatanaka, H. Yokoyama et al., Bull. Chem. Soc. Jpn, vol.70, pp.2215-2219, 1997.

T. F. Schneider, J. Kaschel, and D. B. Werz, Angew. Chem. Int. Ed, vol.53, pp.5504-5523, 2014.

S. Y. Shim, S. M. Cho, A. Venkateswarlu, and D. H. Ryu, Angew. Chem. Int. Ed. Engl, vol.56, pp.8663-8666, 2017.

C. G. Nasveschuk, T. ;. Rovis, M. A. Piotrowski, and . Kerr, Angew. Chem. Int. Ed, vol.44, pp.7624-7627, 2005.

M. E. Alonso, P. Jano, M. I. Hernandez, R. S. Greenberg, and E. Wenkert, Helv. Chim. Acta, vol.48, pp.2159-2165, 1983.

Y. R. Lee and J. C. Hwang, Eur. J. Org. Chem, vol.8, pp.1568-1577, 2005.

). J. Cloke-;-c and . Wilson, J. Am. Chem. Soc, vol.51, pp.3002-3004, 1929.

D. Sperling, H. Reißig, J. Fabian, and L. Ann, Eur. J. Org. Chem, pp.1107-1114, 1997.

). S. Yamaguchi, A. Saitoh, Y. Kawase-;-b, ). S. Yamaguchi, M. Takai et al., Bull. Chem. Soc. Jpn, vol.59, pp.3603-3605, 1986.

S. Levin, R. R. Nani, and S. E. Reisman, J. Am. Chem. Soc, vol.133, pp.774-776, 2011.

D. R. Boyd, D. R. Boyd-;-n, H. M. Snyder, M. W. Haines, and . Peczuh, Comprehensive Heterocyclic Chemistry, vol.7, pp.9301-9320, 1984.

). Y. Asakawa, M. Toyota, T. Takemoto-;-b)-y.-asakawa, E. Kusube, T. Takemoto et al., Phytochemistry, vol.17, pp.235-251, 1978.

M. Stefinovic and V. Snieckus, J. Org. Chem, vol.63, pp.2808-2809, 1998.

M. Yoshida, K. Nakatani, and K. Shishido, Tetrahedron, pp.5702-5708, 2009.

S. Yamaguchi, K. Furihata, M. Miyazawa, H. Yokoyama, and Y. Hirai, Tetrahedron Lett, vol.41, pp.7505-7511, 2000.

R. W. Kierstead, R. P. Linstead, B. C. Weedon-;-r, R. P. Kierstead, B. C. Linstead et al., J. Chem. Soc, vol.1952, pp.1799-1803, 1953.

J. , Chem. Ber, pp.553-565, 1958.

I. F. Valio, R. S. Burdon, W. W. Schwabe, ;. Yoshikawa, Y. Ichiki et al., Biosci. Biotechnol. Biochem, vol.223, pp.840-846, 1969.

, Crystallographic data of compounds 22 and 24 are available free of charge at the Cambridge Crystallographic Data Centre under number CCDC 1890832 and 1890833, respectively

M. Bérubé, F. Kamal, J. Roy, and D. Poirier, Synthesis, vol.18, pp.3085-3091, 2006.

G. R. Ames and W. Davey, J. Chem. Soc, pp.3001-3006, 1956.

C. A. Falciola, K. Tissot-crosset, H. Reyneri, and A. , Adv. Synth. Catal, vol.350, pp.1090-1100, 2008.

). K. Guyton, D. Loomis, Y. Grosse, F. E. Ghissassi, L. Benbrahimtallaa et al., Lancet Oncol, vol.16, p.443, 2015.

S. Andreotti, J. N. Koutros, D. P. Hofmann, J. H. Sandler, C. F. Lubin et al.,

L. E. Silverman and . Freeman, J. Natl. Cancer Inst, vol.110, pp.509-516, 2018.