Synthesis of cis-hydrindan-2,4-diones bearing an all-carbon quaternary center by a Danheiser annulation

• Gisela V. Saborit,
• Carlos Cativiela,
• Ana I. Jiménez,
• Josep Bonjoch and
• Ben Bradshaw

Beilstein J. Org. Chem. 2018, 14, 2597–2601, doi:10.3762/bjoc.14.237

• not relevant for the potential application of this type of building block (i.e., 8) in fawcettimine and related alkaloid synthesis, since this stereogenic center is epimerizable, as shown by Heathcock [7]. Conclusion In summary, we have successfully applied the Danheiser annulation reaction to rapidly

• hydrindan-2,4-diones. Stereoview of cis-hydrindane 8. Decahydroquinoline 1 as a versatile building block for Lycopodium alkaloid synthesis. A de novo approach to 3a-substituted cis-hydrindan-2,4-diones. Synthesis of enone 4 and the Danheiser annulation. The depicted compounds are all racemic. Transformation

Establishing the concept of aza-[3 + 3] annulations using enones as a key expansion of this unified strategy in alkaloid synthesis

• Aleksey I. Gerasyuto,
• Zhi-Xiong Ma,
• Grant S. Buchanan and
• Richard P. Hsung

Beilstein J. Org. Chem. 2013, 9, 1170–1178, doi:10.3762/bjoc.9.131

• synthesis; catalysis; enones; intramolecular aza-[3 + 3] annulation; N-heterocycles; natural product; vinylogous amides; Introduction Throughout the past decade, we have been developing an aza-[3 + 3] annulation reaction as a general and unified strategy in alkaloid synthesis [1][2][3][4][5][6][7][8][9][10

• of isomerization and hydrolysis (Figure 1) [34][35][36][37]. The prevalence of six-membered nitrogen heterocyclic motifs in alkaloids renders the development of this aza-[3 + 3] annulation into a powerful strategy a unique opportunity in the field of alkaloid synthesis [1][2][3][4][8][9][10][11][12

• investigations are underway to pursue alkaloid synthesis via enone aza-[3 + 3] annulation. An aza-[3 + 3] annulation. Possible natural-product targets. Relative stabilities of propyleine and isopropyleine. Aza-[3 + 3] annulations with enones. Synthesis of the annulation precursor enone 10. Propyleine

Manganese dioxide mediated one-pot synthesis of methyl 9H-pyrido[3,4-b]indole-1-carboxylate: Concise synthesis of alangiobussinine

• Jessica Baiget,
• Sabin Llona-Minguez,
• Stuart Lang,
• Simon P. MacKay,
• Colin J. Suckling and
• Oliver B. Sutcliffe

Beilstein J. Org. Chem. 2011, 7, 1407–1411, doi:10.3762/bjoc.7.164

• process for the preparation of methyl 9H-pyrido[3,4-b]indole-1-carboxylate has subsequently been used as the key step in the synthesis of alangiobussinine and a closely related analogue. Keywords: alkaloid synthesis; carboline; heterocycle; oxidation; tandem reaction; Introduction Carbolines are an

Prins fluorination cyclisations: Preparation of 4-fluoro-pyran and -piperidine heterocycles

• Guillaume G. Launay,
• Alexandra M. Z. Slawin and
• David O'Hagan

Beilstein J. Org. Chem. 2010, 6, No. 41, doi:10.3762/bjoc.6.41

• alkaloid synthesis [25][26]. Recently, it has been used to incorporate a halogen atom at the 4 position of a piperidine ring as reported by Carballo et al. [16], and most recently an example incorporating fluorine at the 4-position of a piperidine using Et4NF·5HF has been reported [14][15]. We have

Synthesis of the Benzo- fused Indolizidine Alkaloid Mimics

• Daniel L. Comins and
• Kazuhiro Higuchi

Beilstein J. Org. Chem. 2007, 3, No. 42, doi:10.1186/1860-5397-3-42

• chemical library preparation. Background As part of a program directed at studying the synthesis and synthetic utility of N-acyldihydropyridones, the heterocycles 1 were developed as useful building blocks for alkaloid synthesis (Figure 1). [1][2] Biologically active indolizidine alkaloids [3] such as