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

• convergent approach leveraging an AcOH-interrupted Nazarov cyclization to establish the [5,5,6,6]-tetracyclic scaffold with precise stereochemical fidelity. Results and Discussion Our retrosynthetic analysis toward krishnolides A (7) and C (8) is delineated in Scheme 1B. We hypothesized that these two

• simultaneously installing the hydroxy group at C30. The latter intermediate could in turn be derived from dienone 11 by an AcOH-interrupted Nazarov cyclization [32][33][34], thereby establishing the B ring with the desired all-cis stereochemical configuration, including the quaternary carbon at C10 and the