Photoredox catalysis enabling decarboxylative radical cyclization of γ,γ-dimethylallyltryptophan (DMAT) derivatives: formal synthesis of 6,7-secoagroclavine

• Alessio Regni,
• Francesca Bartoccini and
• Giovanni Piersanti

Beilstein J. Org. Chem. 2023, 19, 918–927, doi:10.3762/bjoc.19.70

• demonstrated by the formal total synthesis of (±)-6,7-secoagroclavine (Scheme 4) [108][109][110][111][112][113][114]. Towards this end, compound 11 was methylated efficiently and selectively at the secondary amide by treatment with methyl iodide in DMF to afford compound 13. In additional two steps

• -catalyzed radical decarboxylative cyclization. Synthesis of compound 5. Photoredox-catalyzed radical decarboxylative cyclization of 5. Synthesis of tryptophan derivatives 8 and 10. Methylation of 11 and the formal total synthesis of (±)-6,7-secoagroclavine. Photoredox-catalyzed radical decarboxylative

1,4-Dithianes: attractive C2-building blocks for the synthesis of complex molecular architectures

• Bram Ryckaert,
• Ellen Demeyere,
• Frederick Degroote,
• Hilde Janssens and
• Johan M. Winne

Beilstein J. Org. Chem. 2023, 19, 115–132, doi:10.3762/bjoc.19.12

• during our (formal) total synthesis of (±)-cephalotaxine (130, Scheme 20b) [112]. Here, the desired desulfurization of a 1,4-dithiane could not be achieved without concomitant migration of an alkene double bond (viz 127 → 128), making the final steps to complete the synthesis quite cumbersome, as at best

Combining the best of both worlds: radical-based divergent total synthesis

• Kyriaki Gennaiou,
• Antonios Kelesidis,
• Maria Kourgiantaki and
• Alexandros L. Zografos

Beilstein J. Org. Chem. 2023, 19, 1–26, doi:10.3762/bjoc.19.1

• (–)-eburnaminol (132), (+)-larutenine (133), (–)-terengganensine B (134), and (–)-strempeliopine (136), as well as the asymmetric formal total synthesis of (–)-terengganensine A (not shown, Scheme 11). The requisite common synthetic intermediate 129 for the cascade was accessed by an acid-promoted condensation of

Formal total synthesis of macarpine via a Au(I)-catalyzed 6-endo-dig cycloisomerization strategy

• Jiayue Fu,
• Bingbing Li,
• Zefang Zhou,
• Maosheng Cheng,
• Lu Yang and
• Yongxiang Liu

Beilstein J. Org. Chem. 2022, 18, 1589–1595, doi:10.3762/bjoc.18.169

• 110016, P. R. China Institute of Drug Research in Medicine Capital of China, Benxi 117000, P. R. China 10.3762/bjoc.18.169 Abstract The formal total synthesis of macarpine was accomplished by the construction of a naphthol intermediate in Ishikawa’s synthetic route with two different synthetic routes

• . The convergent synthetic strategies feature the utilization of Au(I)-catalyzed cycloisomerizations of a 1,5-enyne and alkynyl ketone substrates, which were prepared by Sonogashira coupling reactions. Keywords: benzo[c]phenanthridine alkaloids; 1,5-enyne; formal total synthesis; gold catalysis

• ]. In 2010, Echavarren and co-worker completed the formal total synthesis via a Au(I)-catalyzed cyclization (Scheme 2c) [13]. In 2018, Pabbaraja and co-workers disclosed the synthesis of macarpine by constructing ring C through the domino Michael addition/SNAr reaction of nitromethane to an ynone

Prins cyclization-mediated stereoselective synthesis of tetrahydropyrans and dihydropyrans: an inspection of twenty years

• Asha Budakoti,
• Pradip Kumar Mondal,
• Prachi Verma and
• Jagadish Khamrai

Beilstein J. Org. Chem. 2021, 17, 932–963, doi:10.3762/bjoc.17.77

• produced 90. Similarly, the reaction of 91 produced all-cis-2,3,6-trisubstituted tetrahydropyran 93. The application of this reaction was further extended by an exceptionally concise formal total synthesis of the nuclear export inhibitor (+)-ratjadone A, as shown in Scheme 20. Stereoselective Prins

Progress in the total synthesis of inthomycins

• Bidyut Kumar Senapati

Beilstein J. Org. Chem. 2021, 17, 58–82, doi:10.3762/bjoc.17.7

• concluded that (+)-69 must have (3R)-stereochemistry and they had completed a formal total synthesis of the Zeeck−Taylor [2][21] stereostructure for inthomycin C ((+)-3). To remove any doubt, Stille cross-coupling of 48 with (+)-69 was performed under Ryu’s conditions [50] to give the desired product (+)-11

Pauson–Khand reaction of fluorinated compounds

• Jorge Escorihuela,
• Daniel M. Sedgwick,
• Alberto Llobat,
• Mercedes Medio-Simón,
• Pablo Barrio and
• Santos Fustero

Beilstein J. Org. Chem. 2020, 16, 1662–1682, doi:10.3762/bjoc.16.138

• the regiochemistry for terminal alkynes, affording the products substituted at the β-position. This regiochemistry switch might be regarded as the Holy Grail in Pauson–Khand chemistry. The synthetic potential of this methodology was demonstrated by the formal total synthesis of α-cuparenone [74][75

The synthesis of functionalized bridged polycycles via C–H bond insertion

• Jiun-Le Shih,
• Po-An Chen and
• Jeremy A. May

Beilstein J. Org. Chem. 2016, 12, 985–999, doi:10.3762/bjoc.12.97

• led to a formal total synthesis of garryine, which is closely related to atisine. The initial lactam 26 that was formed by methyl C–H insertion was quite unstable, and so it was quickly converted to the acetamide 27. Advancing that intermediate intercepted a route to garryine completed by Pelletier

Recent applications of ring-rearrangement metathesis in organic synthesis

• Sambasivarao Kotha,
• Milind Meshram,
• Priti Khedkar,
• Shaibal Banerjee and
• Deepak Deodhar

Beilstein J. Org. Chem. 2015, 11, 1833–1864, doi:10.3762/bjoc.11.199

• catalyst 2 in the presence of ethylene (24) to generate the expected rearranged products 254 and 255, respectively (Scheme 52 ). Oxanorbornene systems Lee and co-workers [53] have successfully constructed a fused bis(oxacyclic) system useful towards the formal total synthesis of dysiherbaine and

A carbohydrate approach for the formal total synthesis of (−)-aspergillide C

• Pabbaraja Srihari,
• Namballa Hari Krishna,
• Ydhyam Sridhar and
• Ahmed Kamal

Beilstein J. Org. Chem. 2014, 10, 3122–3126, doi:10.3762/bjoc.10.329

• Medicinal Chemistry & Pharmacology, CSIR-Indian Institute of Chemical Technology, Hyderabad, 500007, India 10.3762/bjoc.10.329 Abstract An enantioselective formal total synthesis of aspergillide C is accomplished using commercially available tri-O-acetyl-D-galactal employing a Ferrier-type C-glycosylation

• approach has been a conventional strategy to achieve the total synthesis of complex, natural products with known handedness. Herein we disclose our strategy for the formal total synthesis of (−)-aspergillide C in a concise manner following the chiron approach. Retrosynthetic Analysis Through a

• achieved the formal total synthesis of (−)-aspergillide C. Conclusion In conclusion, a formal total synthesis of (−)-aspergillide C has been achieved through a concise, stereocontrolled synthesis of the known key intermediate 4 in 8 steps with an overall yield of 36.9% starting from commercially available

Formal total syntheses of classic natural product target molecules via palladium-catalyzed enantioselective alkylation

• Yiyang Liu,
• Marc Liniger,
• Ryan M. McFadden,
• Jenny L. Roizen,
• Jacquie Malette,
• Corey M. Reeves,
• Douglas C. Behenna,
• Masaki Seto,
• Jimin Kim,
• Justin T. Mohr,
• Scott C. Virgil and
• Brian M. Stoltz

Beilstein J. Org. Chem. 2014, 10, 2501–2512, doi:10.3762/bjoc.10.261

• the antipode of (+)-12 using the palladium-catalyzed enantioselective alkylation chemistry described above. We commenced a formal total synthesis of (−)-thujopsene (10) with the goal of improved efficiency compared to the Srikrishna/Anebouselvy route and to use enantioselective palladium catalysis to

• in hand, the formal total synthesis of (−)-thujopsene (10) is completed in only 9 steps from trimethylcyclohexanone 16. B) Quinic acid (−)-Quinic acid (21) [35][36] serves as a useful chiral building block that has been employed in numerous syntheses [37], including our own syntheses of (+)- and

• (−)-dragmacidin F [38][39][40][41], and the initial commercial-scale synthesis of Tamiflu [42]. In Renaud’s formal total synthesis of (−)-quinic acid (21) [35], a key carboxylic acid 22 was accessed, intercepting Novak’s older synthesis of the natural product (Scheme 4) [36]. To begin, Renaud transformed the

Chiral phosphines in nucleophilic organocatalysis

• Yumei Xiao,
• Zhanhu Sun,
• Hongchao Guo and
• Ohyun Kwon

Beilstein J. Org. Chem. 2014, 10, 2089–2121, doi:10.3762/bjoc.10.218

• , Kwon and Andrews completed the first enantioselective total synthesis of the indole alkaloid (+)-ibophyllidine in 15 steps and 13% overall yield from N-Boc-indole-3-aldehyde (Scheme 32) [66]. This approach was the first non-formal total synthesis of a complex natural product employing phosphine

Concise, stereodivergent and highly stereoselective synthesis of cis- and trans-2-substituted 3-hydroxypiperidines – development of a phosphite-driven cyclodehydration

• Peter H. Huy,
• Julia C. Westphal and
• Ari M. P. Koskinen

Beilstein J. Org. Chem. 2014, 10, 369–383, doi:10.3762/bjoc.10.35

• B): 1. Charette [36] prepared the less bioactive enantiomers of L-733,060 and CP-99,994 through nucleophilic additions to chiral pyridylium salts and subsequent hydrogenation. 2. Cossy and Pardo [37][38] synthesized L-733,060 (formal total synthesis) and two (epimeric) hydroxypipecolic acid through

• (synthesized in 6 rather than 8 steps) we also achieved a formal total synthesis of CP-99,994 [87]. Although the phenylalanine and phenylglycine-derived piperidinols 11b and 11c bear “unfunctionalized” side chains, phenyl groups represent masked carboxylic acid functions. For instance, the enantiomers of

A new approach toward the total synthesis of (+)-batzellaside B

• Jolanta Wierzejska,
• Shin-ichi Motogoe,
• Yuto Makino,
• Tetsuya Sengoku,
• Masaki Takahashi and
• Hidemi Yoda

Beilstein J. Org. Chem. 2012, 8, 1831–1838, doi:10.3762/bjoc.8.210

• followed by spontaneous intramolecular cyclization with a yield of 67%. The structural identity of this product was precisely confirmed by 1H NMR spectroscopic data, which proved to be in good agreement with those on record for 4 [19]. Hence, we can conclude that a formal total synthesis of

• . Starting from this chiral material, the formal total synthesis of the heterocyclic hemiaminal 4, a key intermediate elaborated commonly in the first total synthesis, has been achieved in an efficient 21-step protocol in 7.1% overall yield. Furthermore, the stereospecificity in the allylation of 4 has been

Synthetic applications of gold-catalyzed ring expansions

• David Garayalde and
• Cristina Nevado

Beilstein J. Org. Chem. 2011, 7, 767–780, doi:10.3762/bjoc.7.87

• . Formal total synthesis of frondosin A. Gold-catalyzed rearrangement/cycloisomerization of cyclopropyl propargyl acetates. Acknowledgements The authors would like to thank the Organic Chemistry Institute of the University of Zürich for the continuous support and the Swiss National Science Foundation for

A racemic formal total synthesis of clavukerin A using gold(I)-catalyzed cycloisomerization of 3-methoxy-1,6-enynes as the key strategy

• Jae Youp Cheong and
• Young Ho Rhee

Beilstein J. Org. Chem. 2011, 7, 740–743, doi:10.3762/bjoc.7.84

• Jae Youp Cheong Young Ho Rhee Department of Chemistry, POSTECH (Pohang University of Science and Technology), Hyoja-dong san 31, Nam-gu, Pohang, Kyungbook, Republic of Korea 790-784 10.3762/bjoc.7.84 Abstract An efficient formal total synthesis of (±)-clavukerin A was accomplished via a gold

• followed by several other racemic and enantioselective syntheses [2][3][4][5][6][7][8][9][10][11][12][13][14]. Herein, we report a short formal total synthesis of racemic clavukerin A employing the gold(I)-catalyzed cycloisomerization of a 3-methoxy-1,6-enyne as the key strategy, which was recently

Oxidative allylic rearrangement of cycloalkenols: Formal total synthesis of enantiomerically pure trisporic acid B

• Silke Dubberke,
• Muhammad Abbas and
• Bernhard Westermann

Beilstein J. Org. Chem. 2011, 7, 421–425, doi:10.3762/bjoc.7.54

• these carotenoid-derived substances both regulate and stimulate the first stages of sexual development [17][19]. In this publication, the formal total synthesis of optically pure (9Z)-trisporic acid methyl ester (1R,9Z)-4 (Figure 1) will be described, starting from the methyl (1R)-1,3-dimethyl-2