First Total Synthesis and Investigation of the X-ray Crystal Structure of the Pyrano[3,2-a]carbazole Alkaloid Clausenalansine A

Dedicated to Professor Tomáš Hudlický on the occasion of his 71^st birthday

Abstract

We describe the first total synthesis of the recently discovered pyrano[3,2-a]carbazole alkaloid clausenalansine A. The synthetic strategy for the construction of this formylpyrano[3,2-a]carbazole is based on a sequence of Buchwald–Hartwig coupling, palladium(II)-catalyzed oxidative cyclization, Lewis acid promoted annulation of the pyran ring, and chemoselective oxidation of a methyl to a formyl group.

Key words

carbazoles - alkaloids - annulation - catalysis - cyclization - natural products - total synthesis - palladium

Publikationsverlauf

Eingereicht: 07. September 2020

Angenommen nach Revision: 06. Oktober 2020

Artikel online veröffentlicht:
05. November 2020

• References

• 1a Chakraborty DP, Roy S. In Progress in the Chemistry of Organic Natural Products, Vol. 57. Herz W, Grisebach H, Kirby GW, Steglich W, Tamm C. Springer-Verlag; Wien: 1991: 71
• 1b Chakraborty DP. In The Alkaloids, Vol. 44. Cordell GA. Academic Press; New York: 1993: 257
• 2a Knölker H.-J, Reddy KR. Chem. Rev. 2002; 102: 4303
• 2b Knölker H.-J. Top. Curr. Chem. 2005; 244: 115
• 2c Knölker H.-J, Reddy KR. In The Alkaloids, Vol. 65. Cordell GA. Academic Press; Amsterdam: 2008: 1
• 2d Bauer I, Knölker H.-J. Top. Curr. Chem. 2012; 309: 203
• 2e Schmidt AW, Reddy KR, Knölker H.-J. Chem. Rev. 2012; 112: 3193
• 3 Liu Y.-P, Guo J.-M, Liu Y.-Y, Hu S, Yan G, Qiang L, Fu Y.-H. J. Agric. Food Chem. 2019; 67: 5764
• 4a Narasimhan NS, Paradkar MV, Kelkar SL. Indian J. Chem. 1970; 8: 473
• 4b Narasimhan NS, Paradkar MV, Chitguppi VP, Kelkar SL. Indian J. Chem. 1975; 13: 993
• 5 Sriphana U, Thongsri Y, Prariyachatigul C, Pakawatchai C, Yenjai C. Arch. Pharmacal Res. 2013; 36: 1078
• 6a Wu TS. Phytochemistry 1991; 30: 1048
• 6b Ito C, Thoyama Y, Omura M, Kajiura I, Furukawa H. Chem. Pharm. Bull. 1993; 41: 2096
• 6c Songue JL, Kouam ED, Mpondo TN, White RL. Molecules 2012; 17: 13673
• 7 Schuster C, Rönnefahrt M, Julich-Gruner KK, Jäger A, Schmidt AW, Knölker H.-J. Synthesis 2016; 48: 150
• 8 Hesse R, Kataeva O, Schmidt AW, Knölker H.-J. Chem. Eur. J. 2014; 20: 9504
• 9a Julich-Gruner KK, Kataeva O, Schmidt AW, Knölker H.-J. Chem. Eur. J. 2014; 20: 8536
• 9b Schuster C, Julich-Gruner KK, Schnitzler H, Hesse R, Jäger A, Schmidt AW, Knölker H.-J. J. Org. Chem. 2015; 80: 5666
• 10 Part 147 of Transition Metals in Organic Synthesis; for Part 146, see: Lösle V, Knölker H.-J. Arkivoc 2020; vii: 192
• 11a Charles MD, Schultz P, Buchwald SL. Org. Lett. 2005; 7: 3965
• 11b Surry DS, Buchwald SL. Angew. Chem. Int. Ed. 2008; 47: 6338
• 11c Ruiz-Castillo P, Buchwald SL. Chem. Rev. 2016; 116: 12564
• 12a Knölker H.-J, O’Sullivan N. Tetrahedron 1994; 50: 10893
• 12b Knölker H.-J. Chem. Lett. 2009; 38: 8
• 12c Gensch T, Rönnefahrt M, Czerwonka R, Jäger A, Kataeva O, Bauer I, Knölker H.-J. Chem. Eur. J. 2012; 18: 770
• 12d Gensch T, Richter N, Theumer G, Kataeva O, Knölker H.-J. Chem. Eur. J. 2016; 22: 11186
• 13 Hesse R, Gruner KK, Kataeva O, Schmidt AW, Knölker H.-J. Chem. Eur. J. 2013; 19: 14098
• 14a Bandaranayake WM, Begley MJ, Brown BO, Clarke DG, Crombie L, Whiting DA. J. Chem. Soc., Perkin Trans. 1 1974; 998
• 14b Sartori G, Casiraghi G, Bolzoni L, Casnati G. J. Org. Chem. 1979; 44: 803
• 15 Gruner KK, Hopfmann T, Matsumoto K, Jäger A, Katsuki T, Knölker H.-J. Org. Biomol. Chem. 2011; 9: 2057
• 16 CCDC 2017103 (compound 1) contains the supplementary crystallographic data for this paper. The data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/getstructures.