A convergent synthetic approach to the tetracyclic core framework of khayanolide-type limonoids

• Zhiyang Zhang,
• Jialei Hu,
• Hanfeng Ding,
• Li Zhang and
• Peirong Rao

Beilstein J. Org. Chem. 2025, 21, 926–934, doi:10.3762/bjoc.21.75

• the benzylic alcohol, a 1,2-Grignard addition and an AcOH-interrupted Nazarov cyclization. Keywords: enantioselective synthesis; interrupted Nazarov cyclization; khayanolide-type limonoids; tetracyclic framework; Introduction Limonoids, a class of tetranortriterpenoids derived biosynthetically from

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

• material, the bridged tetracyclic framework of the Alstonia class of indole alkaloids was readily formed in high yield. This asymmetric [4 + 2] annulation was a seminal advance in the area of nucleophilic phosphine catalysis, attracting much attention toward chiral phosphine-catalyzed asymmetric reactions

Mitomycins syntheses: a recent update

• Jean-Christophe Andrez

Beilstein J. Org. Chem. 2009, 5, No. 33, doi:10.3762/bjoc.5.33

• selectively reduced to the corresponding amine with stannous chloride and thiophenol and the aziridine was fashioned by protection of the primary amine followed by an intramolecular Mistunobu reaction. The tetracyclic framework was completed by an intramolecular Michael addition to give desmethoxymitomycin A

Sordarin, an antifungal agent with a unique mode of action

• Huan Liang

Beilstein J. Org. Chem. 2008, 4, No. 31, doi:10.3762/bjoc.4.31

• carboxylic acid, and the tetracyclic framework, are unknown. The total syntheses presented previously did not address these issues. However, it is established that the aldehyde function may be replaced by a nitrile group without loss of activity [42]. Efforts aiming to elucidate the role – if any – of the

• subunits of the aglycone have been described by Cuevas and by Ciufolini. Highlights of these contributions are outlined below. Cuevas’s cyclopentane analog Modeling studies by Cuevas et al. relying on the INSIGHT software [43][44] reduced the tetracyclic framework of sordarin to a simple cyclopentane

• cyclopentadiene 13. Synthesis of sordaricin methyl ester. Mander’s retrosynthetic plan. Synthesis of iodo compound 27. Synthesis of sordaricin (2). Retrosynthesis of sordarin and sordaricin. Synthesis of ketone 43. Synthesis of β-keto ethyl ester 45. Synthesis of tetracyclic framework 52. Synthesis of sordaricin