Catalytic enantioselective nitrone cycloadditions enabling collective syntheses of indole alkaloids

Maity, P., Adhikari, D. & Jana, A. K. An overview on synthetic entries to tetrahydro-β-carbolines. Tetrahedron 75, 965–1028 (2019).Article 
CAS 

Google Scholar 
Wang, J. et al. A review of synthetic bioactive tetrahydro-β-carbolines: a medicinal chemistry perspective. Eur. J. Med. Chem. 225, 113815 (2021).Article 
CAS 
PubMed 

Google Scholar 
Glinsky-Olivier, N. & Guinchard, X. Enantioselective catalytic methods for the elaboration of chiral tetrahydro-β-carbolines and related scaffolds. Synthesis 49, 2605–2620 (2017).Article 
CAS 

Google Scholar 
Seayad, J., Seayad, A. M. & List, B. Catalytic asymmetric Pictet–Spengler reaction. J. Am. Chem. Soc. 128, 1086–1087 (2006).Article 
CAS 
PubMed 

Google Scholar 
Stöckigt, J., Antonchick, A. P., Wu, F. & Waldmann, H. The Pictet–Spengler reaction in nature and in organic chemistry. Angew. Chem. Int. Ed. 50, 8538–8564 (2011).Article 

Google Scholar 
Wang, S.-G. et al. Construction of chiral tetrahydro-β-carbolines: asymmetric Pictet–Spengler reaction of indolyl dihydropyridines. Angew. Chem. Int. Ed 56, 7440–7443 (2017).Article 
ADS 
CAS 

Google Scholar 
Klausen, R. S., Kennedy, C. R., Hyde, A. M. & Jacobsen, E. N. Chiral thioureas promote enantioselective Pictet–Spengler cyclization by stabilizing every intermediate and transition state in the carboxylic acid-catalyzed reaction. J. Am. Chem. Soc. 139, 12299–12309 (2017).Article 
CAS 
PubMed 
PubMed Central 

Google Scholar 
Pressnitz, D. et al. Asymmetric synthesis of (R)-1-alkyl-substituted tetrahydro-β-carbolines catalyzed by strictosidine synthases. Angew. Chem. Int. Ed 57, 10683–10687 (2018).Article 
CAS 

Google Scholar 
Qi, L., Hou, H., Ling, F. & Zhong, W. The cinchona alkaloid squaramide catalyzed asymmetric Pictet–Spengler reaction and related theoretical studies. Org. Biomol. Chem. 16, 566–574 (2018).Article 
CAS 
PubMed 

Google Scholar 
Kim, A. et al. Catalytic and enantioselective control of the C-N stereogenic axis via the Pictet–Spengler reaction. Angew. Chem. Int. Ed. 60, 12279–12283 (2021).Article 
CAS 

Google Scholar 
Chan, Y.-C., Sak, M. H., Frank, S. A. & Miller, S. J. Tunable and cooperative catalysis for enantioselective Pictet–Spengler reaction with varied nitrogen-containing heterocyclic carboxaldehydes. Angew. Chem. Int. Ed. 60, 24573–24581 (2021).Article 
CAS 

Google Scholar 
Li, C. & Xiao, J. Asymmetric hydrogenation of cyclic Imines with an Ionic Cp*Rh(III) catalyst. J. Am. Chem. Soc. 130, 13208–13209 (2008).Article 
CAS 
PubMed 

Google Scholar 
da Silva, W. A. et al. Novel supramolecular palladium catalyst for the asymmetric reduction of imines in aqueous media. Org. Lett. 11, 3238–3241 (2009).Article 
PubMed 

Google Scholar 
Liu, Y. et al. Enantioselective synthesis of indoloquinolizidines via asymmetric catalytic hydrogenation/lactamization of imino diesters. J. Org. Chem. 78, 12009–12017 (2013).Article 
CAS 
PubMed 

Google Scholar 
Zhang, W. et al. Stereoselective total syntheses of C18-oxo eburnamine-vincamine alkaloids. Org. Lett. 24, 2409–2413 (2022).Article 
CAS 
PubMed 

Google Scholar 
Zhang, W. et al. Enantioselective total syntheses of (−)-20-epi-vincamine and (−)-20-epi-eburnamonine by Ir-catalyzed asymmetric imine hydrogenation/lactamization cascade. Chem. Eur. J. 26, 10439–10443 (2020).Article 
CAS 
PubMed 

Google Scholar 
Ji, Y. et al. Iridium-catalyzed asymmetric hydrogenation of cyclic iminium salts. Org. Chem. Front. 4, 1125–1129 (2017).Article 
CAS 

Google Scholar 
Yang, L. et al. Asymmetric synthesis of fused-ring tetrahydroisoquinolines and tetrahydro-β-carbolines from 2‑arylethylamines via a chemoenzymatic approach. Org. Lett. 24, 6531–6536 (2022).Article 
CAS 
PubMed 

Google Scholar 
Itoh, T., Yokoya, M., Miyauchi, K., Nagata, K. & Ohsaw, A. Proline-catalyzed asymmetric addition reaction of 9-tosyl-3,4-dihydro-β-carboline with ketones. Org. Lett. 5, 4301–4304 (2003).Article 
CAS 
PubMed 

Google Scholar 
Lalonde, M. P., McGowan, M. A., Rajapaksa, N. S. & Jacobsen, E. N. Enantioselective formal aza-Diels-Alder Reactions of enones with cyclic imines catalyzed by primary aminothioureas. J. Am. Chem. Soc. 135, 1891–1894 (2013).Article 
CAS 
PubMed 
PubMed Central 

Google Scholar 
Zhang, M. et al. Phosphoric acid catalyzed asymmetric [2+2] cyclization/penicillin-penillonic acid rearrangement. Angew. Chem. Int. Ed. 57, 4921–4925 (2018).Article 
ADS 
CAS 

Google Scholar 
Liu, X., Meng, Z., Li, C., Lou, H. & Liu, L. Organocatalytic enantioselective oxidative C‒H alkenylation and arylation of N-carbamoyl tetrahydropyridines and tetrahydro-β-carbolines. Angew. Chem. Int. Ed. 54, 6012–6015 (2015).Article 
CAS 

Google Scholar 
Wei, G. et al. Enantioselective aerobic oxidative C(sp3) ‒H olefination of amines via cooperative photoredox and asymmetric catalysis. ACS Catal. 6, 3708–3712 (2016).Article 
CAS 

Google Scholar 
Liang, L., Zhou, S., Zhang, W. & Tong, R. Catalytic asymmetric alkynylation of 3,4-dihydro-β-carbolinium ions enables collective total syntheses of indole alkaloids. Angew. Chem. Int. Ed. 60, 25135–25142 (2021).Article 
CAS 

Google Scholar 
Zheng, H. et al. Regio- and enantioselective aza-Diels-Alder reactions of 3-vinylindoles: a concise synthesis of the antimalarial spiroindolone NITD609. Angew. Chem. Int. Ed. 54, 10958–10962 (2015).Article 
CAS 

Google Scholar 
Wang, Y. et al. Gold-catalyzed asymmetric intramolecular cyclization of N-allenamides for the synthesis of chiral tetrahydrocarbolines. Angew. Chem. Int. Ed. 56, 15905–15909 (2017).Article 
ADS 
CAS 

Google Scholar 
Ye, C. et al. Copper(I)-catalyzed asymmetric [3 + 3] annulation involving aziridines to construct tetrahydro-β-carbolines. Org. Chem. Front. 7, 3393–3398 (2020).Article 
CAS 

Google Scholar 
Rajasekar, S. & Anbarasan, P. Tandem Rh(II) and chiral squaramide relay catalysis: enantioselective synthesis of dihydro-β-carbolines via insertion to C‒H bond and aza-Michael reaction. Org. Lett. 21, 3067–3071 (2019).Article 
CAS 
PubMed 

Google Scholar 
Chen, J., Han, X. & Lu, X. Palladium(II)-catalyzed asymmetric tandem cyclization of 2-aminoaryl alkynones: an approach to chiral 1,2,3,4-tetrahydro-β-carbolines. Org. Lett. 20, 7470–7473 (2018).Article 
CAS 
PubMed 

Google Scholar 
Bandini, M. et al. Highly enantioselective synthesis of tetrahydro-β-carbolines and tetrahydro-γ-carbolines via Pd-catalyzed intramolecular allylic alkylation. J. Am. Chem. Soc. 128, 1424–1425 (2006).Article 
CAS 
PubMed 

Google Scholar 
Cai, Q., Zhao, Z.-A. & You, S.-L. Asymmetric construction of polycyclic indoles through olefin cross-metathesis/Intramolecular Friedel-Crafts alkylation under sequential catalysis. Angew. Chem. Int. Ed. 48, 7428–7431 (2009).Article 
CAS 

Google Scholar 
Xu, Q.-L., Zhuo, C.-X., Dai, L.-X. & You, S.-L. Highly enantioselective synthesis of tetrahydrocarbolines via Iridium-catalyzed intramolecular Friedel-Crafts type allylic alkylation reactions. Org. Lett. 15, 5909–5911 (2013).Article 
CAS 
PubMed 

Google Scholar 
Zhuo, C.-X., Wu, Q.-W., Zhao, Q., Xu, Q.-L. & You, S.-L. Enantioselective functionalization of indoles and pyrroles via an in situ-formed spiro intermediate. J. Am. Chem. Soc. 135, 8169–8172 (2013).Article 
CAS 
PubMed 

Google Scholar 
Muratore, M. E. et al. Enantioselective Brønsted acid-catalyzed N-acyliminium cyclization cascades. J. Am. Chem. Soc. 131, 10796–10797 (2009).Article 
CAS 
PubMed 

Google Scholar 
Holloway, C. A., Muratore, M. E., Storer, R. I. & Dixon, D. J. Direct enantioselective Brønsted acid catalyzed N-acyliminium cyclization cascades of tryptamines and ketoacids. Org. Lett. 12, 4720–4723 (2010).Article 
CAS 
PubMed 

Google Scholar 
Hofmann, F., Gärtner, C., Kretzschmar, M. & Schneider, C. Asymmetric synthesis of fused tetrahydroquinolines via intra­molecular Aza-Diels-Alder reaction of ortho-quinone methide Imines. Synthesis 54, 1055–1080 (2022).Article 
CAS 

Google Scholar 
Raheem, I. T., Thiara, P. S., Peterson, E. A. & Jacobsen, E. N. Enantioselective Pictet–Spengler-type cyclizations of hydroxylactams: H-bond donor catalysis by anion binding. J. Am. Chem. Soc. 129, 13404–13405 (2007).Article 
CAS 
PubMed 

Google Scholar 
Bou-Hamdan, F. R. & Leighton, J. L. Highly enantioselective Pictet–Spengler reactions with α-Ketoamide-derived ketimines: access to an unusual class of quaternary α-amino amides. Angew. Chem. Int. Ed. 48, 2403–2406 (2007).Article 

Google Scholar 
Piemontesi, C., Wang, Q. & Zhu, J. Enantioselective synthesis of (+)-peganumine A. J. Am. Chem. Soc. 138, 11148–11151 (2016).Article 
CAS 
PubMed 

Google Scholar 
Xie, E., Rahman, A. & Lin, X. Asymmetric synthesis of CF3—and indole-containing tetrahydro-β-carbolines via chiral spirocyclic phosphoric acid-catalyzed aza-Friedel-Crafts reaction. Org. Chem. Front. 4, 1407–1410 (2017).Article 
CAS 

Google Scholar 
Andres, R., Wang, Q. & Zhu, J. Asymmetric total synthesis of (−)-arborisidine and (−)-19-epi arborisidine enabled by a catalytic enantioselective Pictet–Spengler reaction. J. Am. Chem. Soc. 142, 14276–14285 (2020).Article 
CAS 
PubMed 

Google Scholar 
Lynch-Colameta, T., Greta, S. & Snyder, S. A. Synthesis of aza-quaternary centers via Pictet–Spengler reactions of ketonitrones. Chem. Sci. 12, 6181–6187 (2021).Article 
CAS 
PubMed 
PubMed Central 

Google Scholar 
He, G., List, B. & Christmann, M. Unified synthesis of polycyclic alkaloids by complementary carbonyl activation. Angew. Chem. Int. Ed. 60, 13591–13596 (2021).Article 
CAS 

Google Scholar 
Nakamura, S., Matsuda, Y., Takehara, T. & Suzuki, T. Enantioselective Pictet–Spengler reaction of acyclic α-ketoesters using chiral imidazoline-phosphoric acid catalysts. Org. Lett. 24, 1072–1076 (2022).Article 
CAS 
PubMed 

Google Scholar 
Andres, R., Wang, Q. & Zhu, J. Catalytic enantioselective Pictet–Spengler reaction of α-ketoamides catalyzed by a single H-bond donor organocatalyst. Angew. Chem. Int. Ed. 61, e202201788 (2022).Article 
ADS 
CAS 

Google Scholar 
Andres, R., Sun, F., Wang, Q. & Zhu, J. Organocatalytic enantioselective Pictet–Spengler reaction of α-Ketoesters: development and application to the total synthesis of (+)-alstratine A. Angew. Chem. Int. Ed. 62, e202213831 (2023).Article 
CAS 

Google Scholar 
Long, D. et al. Enantioselective Pictet–Spengler condensation to access the total synthesis of (+)-tabertinggine. Eur. J. Org. Chem. 2022, e202200088 (2022).Article 
ADS 
CAS 

Google Scholar 
Shirakawa, S., Liu, K., Itoa, H. & Maruoka, K. Catalytic asymmetric synthesis of 1,1-disubstituted tetrahydro-β-carbolines by phase-transfer catalyzed alkylations. Chem. Commun. 47, 1515–1517 (2011).Article 
CAS 

Google Scholar 
Fang, F., Hua, G., Shi, F. & Li, P. Organocatalytic enantioselective Friedel-Crafts reaction: an efficient access to chiral isoindolo-β-carboline derivatives. Org. Biomol. Chem. 13, 4395–4398 (2015).Article 
CAS 
PubMed 

Google Scholar 
Kruegel, A. C. et al. Synthetic and receptor signaling explorations of the mitragyna alkaloids: mitragynine as an atypical molecular framework for opioid receptor modulators. J. Am. Chem. Soc. 138, 6754–6764 (2016).Article 
CAS 
PubMed 
PubMed Central 

Google Scholar 
Piemontesi, C., Wang, Q. & Zhu, J. Enantioselective total synthesis of (−)-terengganensine A. Angew. Chem. Int. Ed. 55, 6556–6560 (2016).Article 
CAS 

Google Scholar 
Wang, X. et al. A radical cascade enabling collective syntheses of natural products. Chem 2, 803–816 (2017).Article 
CAS 

Google Scholar 
Zheng, Y., Wei, K. & Yang, Y.-R. Total synthesis of (−)-geissoschizol through Ir-catalyzed allylic amidation as the key step. Org. Lett. 19, 6460–6462 (2017).Article 
CAS 
PubMed 

Google Scholar 
Liu, X.-Y. & Qin, Y. Recent advances in the total synthesis of monoterpenoid indole alkaloids enabled by asymmetric catalysis. Green Synth. Catal. 3, 25–39 (2022).Article 
CAS 

Google Scholar 
Plate, R., Hermkens, P. H. H., Smits, J. M. M. & Ottenheijm, H. C. J. Nitrone cycloaddition in the stereoselective synthesis of β-carbolines from N-hydroxytryptophan. J. Org. Chem. 51, 309–314 (1986).Article 
CAS 

Google Scholar 
Plate, R., Hermkens, P. H. H., Smits, J. M. M., Nivard, R. J. F. & Ottenheijm, H. C. J. Employment of nitriles in the stereoselective cycloaddition to nitrones. J. Org. Chem. 52, 1047–1051 (1987).Article 
CAS 

Google Scholar 
Hemkens, P. H. H., Maarsevttn, J. H. V., Kruse, C. G. & Scheeren, H. W. 1,3-Dipolar cycloaddition of nitrones with nitriles.: scope and mechanistic study. Tetrahedron 44, 6491–6504 (1988).Article 

Google Scholar 
Brandi, A. et al. Rearrangement of isoxazoline-5-spiro derivatives. 2. synthesis and rearrangement of tetrahydroisoxazole-5-spirocyclopropanes. preparation of precursors of quinolizine, isoquinoline, and indole alkaloids. J. Org. Chem. 53, 2430–2434 (1988).Article 
CAS 

Google Scholar 
Black, D. S. C., Deb-Das, R. B., Kumar, N. & Wright, T. A. Synthesis of new heterocyclic systems by 1,3-dipolar cycloaddition reactions of dihydro-β-carboline n-oxides with alkynes. Tetrahedron Lett 33, 839–840 (1992).Article 
CAS 

Google Scholar 
Black, D. S. C., Craig, D. C., Deb-Das, R. B., Kumar, N. & Wright, T. A. Nitrones and oxaziridines. XLVII Intermolecular cycloaddition of fused indolyl nitrone ring systems. Aust. J. Chem. 46, 1725–1742 (1993).Article 
CAS 

Google Scholar 
Moriyama, S. & Vallée, Y. 1,3-Dipolar cycloaddition reaction of 3,4-dihydro-β-carboline 2-oxide. Synthesis 1998, 393–404 (1998).Article 

Google Scholar 
Jiao, P., Nakashima, D. & Yamamoto, H. Enantioselective 1,3-dipolar cycloaddition of nitrones with ethyl vinyl ether: the difference between Brønsted and Lewis acid catalysis. Angew. Chem. Int. Ed. 47, 2411–2413 (2008).Article 
CAS 

Google Scholar 
Jin, Y., Honma, Y., Morita, H., Miyagawa, M. & Akiyama, T. Enantioselective synthesis of 1-substituted 1,2,3,4-Tetrahydro-isoquinolines through 1,3-dipolar cycloaddition by a chiral phosphoric acid. Synlett 30, 1541–1545 (2019).Article 
CAS 

Google Scholar 
Akiyama, T., Itoh, J., Yokota, K. & Fuchibe, K. Enantioselective Mannich-type reaction catalyzed by a chiral Brønsted acid. Angew. Chem. Int. Ed. 43, 1566–1568 (2004).Article 
CAS 

Google Scholar 
Uraguchi, D. & Terada, M. Chiral Brønsted acid-catalyzed direct Mannich reactions via electrophilic activation. J. Am. Chem. Soc. 126, 5356–5357 (2004).Article 
CAS 
PubMed 

Google Scholar 
Akiyama, T. Stronger Brønsted acids. Chem. Rev. 107, 5744–5758 (2007).Article 
CAS 
PubMed 

Google Scholar 
Terada, M. Chiral phosphoric acids as versatile catalysts for enantioselective transformations. Synthesis 2010, 1929–1982 (2010).Article 

Google Scholar 
Parmar, D., Sugiono, E., Raja, S. & Rueping, M. Complete field guide to asymmetric binol-phosphate derived Brønsted acid and metal catalysis: history and classification by mode of activation; Brønsted acidity, hydrogen bonding, ion pairing, and metal phosphates. Chem. Rev. 114, 9047–9153 (2014).Article 
CAS 
PubMed 

Google Scholar 
Parmar, D., Sugiono, E., Raja, S. & Rueping, M. Complete field guide to asymmetric binol-phosphate derived Brønsted acid and metal catalysis: history and classification by mode of activation; Brønsted acidity, hydrogen bonding, ion pairing, and metal phosphates. Chem. Rev. 117, 10608–10620 (2017).Article 
CAS 
PubMed 

Google Scholar 
Merad, J., Lalli, G., Bernadat, G., Maur, J. & Masson, G. Enantioselective Brønsted acid catalysis as a tool for the synthesis of natural products and pharmaceuticals. Chem. Eur. J. 24, 3925–3943 (2018).Article 
CAS 
PubMed 

Google Scholar 
Maji, R., Mallojjala, S. C. & Wheeler, S. E. Chiral phosphoric acid catalysis: from numbers to insights. Chem. Soc. Rev. 47, 1142–1158 (2018).Article 
CAS 
PubMed 

Google Scholar 
Li, X. & Song, Q. Recent advances in asymmetric reactions catalyzed by chiral phosphoric acids. Chin. Chem. Lett. 29, 1181–1192 (2018).Article 
CAS 

Google Scholar 
Rahman, A. & Lin, X. Development and application of chiral spirocyclic phosphoric acids in asymmetric catalysis. Org. Biomol. Chem. 16, 4753–4777 (2018).Article 
CAS 
PubMed 

Google Scholar 
Liu, W. & Yang, X. Recent advances in (dynamic) kinetic resolution and desymmetrization catalyzed by chiral phosphoric acids. Asian J. Org. Chem. 10, 692–710 (2021).Article 
CAS 

Google Scholar 
Walton, M. C., Yang, Y.-F., Hong, X., Houk, K. N. & Overman, L. E. Ligand-controlled diastereoselective 1,3-dipolar cycloadditions of azomethine ylides with methacrylonitrile. Org. Lett. 17, 6166–6169 (2015).Article 
CAS 
PubMed 

Google Scholar 
Newberry, R. W. & Raines, R. T. The n→π* Interaction. Acc. Chem. Res. 50, 1838–1846 (2017).Article 
CAS 
PubMed 
PubMed Central 

Google Scholar 
Murahashi, S. I., Kodera, Y. & Hosomi, T. A novel oxidative ring-opening reaction of isoxazolidines: syntheses of β-amino ketones and β-amino acid esters from secondary amines. Tetrahedron Lett 29, 5949–5952 (1988).Article 
CAS 

Google Scholar 
Nguyen, T. B. et al. Access to α-substituted amino acid derivatives via 1,3-dipolar cycloaddition of α-amino ester derived nitrones. J. Org. Chem. 75, 611–620 (2010).Article 
CAS 
PubMed 

Google Scholar 
Kam, T.-S. & Sim, K.-M. Alkaloids from Kopsia griffithii. Phytochemistry 47, 145–147 (1998).Article 
CAS 

Google Scholar 
Spindola, H. M. et al. The antinociceptive activity of harmicine on chemical-induced neurogenic and inflammatory pain models in mice. Pharmacol. Biochem. Behav. 102, 133–138 (2012).Article 
CAS 
PubMed 

Google Scholar 
Chbani, M., Païs, M., Delauneux, J. M. & Debitus, C. Brominated indole alkaloids from the marine tunicate Pseudodistoma arborescens. J. Nat. Prod. 56, 99–104 (1993).Article 
CAS 
PubMed 

Google Scholar 
Santos, L. S., Theoduloz, C., Pilli, R. A. & Rodriguez, J. Antiproliferative activity of arborescidine alkaloids and derivatives. Eur. J. Med. Chem. 44, 3810–3815 (2009).Article 
CAS 
PubMed 

Google Scholar 
Mujahid, M. & Muthukrishnan, M. A new enantioselective synthesis of the anticonvulsant drug pregabalin (Lyrica) based on a hydrolytic kinetic resolution method. Chirality 25, 965–969 (2013).Article 
CAS 
PubMed 

Google Scholar 
Lim, K.-H., Komiyama, K. & Kam, T.-S. Arboricine and arboricinine, unusual tetracyclic indole regioisomers from Kopsia. Tetrahedron Lett. 48, 1143–1145 (2007).Article 
CAS 

Google Scholar 
Feng, X. Z., Kan, C., Potier, P., Kan, S. K. & Lounasmaa, M. Monomeric indole alkaloids from Ervatamia hainanensis. Planta. Med. 44, 212–214 (1982).Article 
CAS 
PubMed 

Google Scholar 
Vamvacas, V. C., Philipsborn, W. V., Schlittler, E., Schmid, H. & Karrer, P. Über die konstitution des melinonins B. 26. mitteilung über calebassen-alkaloide. Helvetica. Chimica. Acta. 40, 1793–1808 (1957).Article 
CAS 

Google Scholar 
Shellard, E. J. & Houghton, P. J. The mitragyna species of asia Part XXIV. The isolation of dihydrocorynantheol and corynantheidol from the leaves of Mitragyna parvifolia (Roxb.) Korth from Sri Lanka (Ceylon). Planta. Med. 24, 13–17 (1973).Article 
CAS 
PubMed 

Google Scholar 
Gilbert, B., Antonaccio, L. D. & Djerassi, C. Alkaloid studies. XXXIX. Occurrence of dihydrocorynantheol and aricine in Aspidosperma maregravianum Woodson. J. Org. Chem. 27, 4702–4704 (1962).Article 
CAS 

Google Scholar 
Robert, G. M. T. et al. Aspidosperma de guyane: alcaloïdes de Aspidosperma marcgravianum. J. Nat. Prod. 46, 694–707 (1983).Article 
CAS 

Google Scholar 
Weniger, B. et al. Indole alkaloids from Antirhea portoricensis. J. Nat. Prod. 57, 287–290 (1994).Article 
CAS 

Google Scholar 
Zhang, Y. et al. Brønsted acid-catalyzed highly stereoselective arene-ynamide cyclizations. a novel keteniminium Pictet–Spengler cyclization in total syntheses of (±)-desbromoarborescidines A and C. Org. Lett. 7, 1047–1050 (2005).Article 
CAS 
PubMed 

Google Scholar 
Li, G., Piemontesi, C., Wang, Q. & Zhu, J. Stereoselective total synthesis of eburnane-type alkaloids enabled by conformation-directed cyclization and rearrangement. Angew. Chem. Int. Ed. 58, 2870–2874 (2019).Article 
CAS 

Google Scholar 
Ramakrishna, G. V. et al. Streamlined strategy for scalable and enantioselective total syntheses of the eburnane alkaloids. J. Am. Chem. Soc. 145, 20062–20072 (2023).Article 
CAS 
PubMed 

Google Scholar 
Andriamialisoa, R. Z., Langlois, N. & Langlois, Y. A new efficient total synthesis of vindorosine and vindoline. J. Org. Chem. 50, 961–967 (1985).Article 
CAS 

Google Scholar 
Liu, H.-M., Wu, B., Zheng, Q.-T. & Feng, X.-Z. New indole alkaloids from Amsonia sinensis. Planta. Med. 57, 566–568 (1991).Article 
CAS 
PubMed 

Google Scholar 
Pegnyemb, D. E., Ghogomu, R. T. & Sondengam, B. L. Minor alkaloids from the seeds of Voacanga africana. Fitoterapia 70, 446–448 (1999).Article 
CAS 

Google Scholar 
Chong, K.-W. et al. Biosynthetic enantiodivergence in the eburnane alkaloids from Kopsia. J. Nat. Prod. 80, 3014–3024 (2017).Article 
CAS 
PubMed 

Google Scholar 
Gan, C.-Y. et al. Leuconicines A-G and (−)-eburnamaline, biologically active strychnan and eburnan alkaloids from Leuconotis. J. Nat. Prod. 72, 2098–2103 (2009).Article 
CAS 
PubMed 

Google Scholar 
Wong, S.-P. et al. Arborisidine and arbornamine, two monoterpenoid indole alkaloids with new polycyclic carbon-nitrogen skeletons derived from a common pericine precursor. Org. Lett. 18, 1618–1621 (2016).Article 
CAS 
PubMed 

Google Scholar 
Frisch, M. J., et al. Gaussian 16, revision C.01. (Gaussian, Inc: Wallingford, CT, 2019).Lenin, D. S., Aníbal, S., Rafael, A. & Marco, A. C. N. Theoretical study of the adsorption of alkylamines in h-mordenite: the role of noncovalent interactions. J. Phys. Chem. C 119, 8112–8123 (2015).Article 

Google Scholar 
Hariharan, P. C. & Pople, J. A. The influence of polarization functions on molecular orbital hydrogenation energies. Theor. Chim. Acta 28, 213–222 (1973).Article 
CAS 

Google Scholar 
Hehre, W. J., Ditchfield, R. & Pople, J. A. Self-consistent molecular orbital methods. XII. Further extensions of Gaussian-type basis sets for use in molecular orbital studies of organic molecules. J. Chem. Phys. 56, 2257–2261 (1972).Article 
ADS 
CAS 

Google Scholar 
Ditchfield, R., Hehre, W. J. & Pople, J. A. Self-consistent molecular-orbital methods. IX. An extended Gaussian-type basis for molecular-orbital studies of organic molecules. J. Chem. Phys. 54, 724–728 (1971).Article 
ADS 
CAS 

Google Scholar 
Marenich, A. V., Cramer, C. J. & Truhlar, D. G. Universal solvation model based on solute electron density and on a continuum model of the solvent defined by the bulk dielectric constant and atomic surface tensions. J. Phys. Chem. B 113, 6378–6396 (2009).Article 
CAS 
PubMed 

Google Scholar 
Legault, C. Y., CYLview, 1.0b, Université de Sherbrooke, Canada, https://www.cylview.org (2009).