Tetrahedron Letters, Год журнала: 2024, Номер 155, С. 155437 - 155437
Опубликована: Дек. 31, 2024
Язык: Английский
Chemistry - A European Journal, Год журнала: 2023, Номер 29(68)
Опубликована: Сен. 13, 2023
Total syntheses of C11-oxygenated Cephalotaxus alkaloids, fortuneicyclidins A and B, cephalotine were achieved. The key for the synthesis is a Pd-catalyzed dearomative spirocyclization bromofurans with N-tosylhydrazones, followed by acid-mediated tandem transformation to construct tetracyclic skeleton C11-oxygen functional group. Chemo-selective catalytic group conversions intermediate completed B in 8 9 steps, respectively.
Язык: Английский
Процитировано
6
Опубликована: Дек. 4, 2023
Six undescribed cephalotane-type diterpenoids and/or norditerpenoids, ceforloids A–F (1–6), were isolated from Cephalotaxus fortunei var. alpina and C. sinensis. Their structures elucidated by comprehensive analysis of spectroscopic data. Compound 1 possesses an unprecedented norditerpenoid skeleton featuring unusual acetophenone moiety, originated putatively a disparate biogenetic pathway. Compounds 4 5 incorporate unique 12,13-p-hydroxybenzylidene acetal motif. 6 is rare diterpenoid glycoside. Immunosuppressive assays showed that compounds 2 exhibited mild suppressive activity against the activated T B lymphocytes proliferation.
Язык: Английский
Процитировано
5
Organic Letters, Год журнала: 2023, Номер 25(41), С. 7459 - 7463
Опубликована: Авг. 14, 2023
Cephalotine A, a recently isolated Cephalotaxus alkaloid, was first synthesized enantioselectively through three critical reactions. SmI2 -mediated radical cyclization of lactone and aldehyde to forge the final ring system, Chang's iridium-catalyzed C-H amidation construct pyrrolidone stereoselectively, Carreria's dual Ir/amine catalyzed allylation install vicinal tertiary stereocenters.
Язык: Английский
Процитировано
4
Elsevier eBooks, Год журнала: 2024, Номер unknown
Опубликована: Янв. 1, 2024
Язык: Английский
Процитировано
1
Organic Letters, Год журнала: 2023, Номер 25(41), С. 7464 - 7469
Опубликована: Окт. 6, 2023
Fortuneicyclidins A and B are a pair of recently isolated Cephalotaxus alkaloids with an unprecedented rearranged polycyclic skeleton possessing multiple complex stereocenters functionalization. In this work, highly stereocontrolled asymmetric total syntheses for title were outlined. Key features include underexplored Ir-catalyzed α-allylation aldehyde to strategically install vicinal N-substituted quaternary center tertiary stereocenter, Heck RCM reactions construct the critical framework rapidly, two different tandem oxidation–transannular aldol cyclization processes, one through ozonolysis another via Swern oxidation, forge last ring fortuneicyclidins B, respectively. approach, challenging C-2 hydroxyl group can be installed stereospecifically.
Язык: Английский
Процитировано
3
Chemistry - A European Journal, Год журнала: 2023, Номер 30(13)
Опубликована: Дек. 12, 2023
Abstract A convenient and versatile approach to important 1‐azaspirocyclic systems relevant medicinal chemistry natural products is reported herein. The main strategy relies on a reductive decarboxylative cyclization of redox‐active esters which can be rapidly assembled from abundant cyclic azaacids tailored acceptor sidechains, with focus alkyne acceptors enabling the generation useful exo ‐alkene moieties. Diastereoconvergent variants were studied could achieved either through remote stereocontrol or conformational restriction in bicyclic carbamate substrates. Two sets metal‐free photocatalytic conditions employing inexpensive eosin Y disclosed experimentally highlight key mechanistic divergences.
Язык: Английский
Процитировано
1
Journal of Synthetic Organic Chemistry Japan, Год журнала: 2024, Номер 82(10), С. 965 - 978
Опубликована: Окт. 1, 2024
Dearomative functionalization is a powerful method to construct structurally complex alicyclic frameworks from simple and abundant aromatic molecules. Although myriad of dearomative functionalizations have been reported so far, the reaction electron-neutral arenes such as benzenes naphthalenes are still challenging issue due their high stability, often requiring an excess amount starting materials. Recently, we developed catalytic by focusing on unique reactivity π-benzyl palladium catalysis. In this manuscript, describe our endeavor develop C-C bond formations benzyl alcohol derivatives, ammoniums, bromoarenes. The dearomatized compound was transformed into various skeletons diverse derivatizations. Furthermore, successfully achieved C-N formation with bromo(hetero)arenes, resulting in synthesis azaspirocycles. Utilizing present methodology, total Cephalotaxus alkaloids polycyclic skeleton, has also accomplished.
Язык: Английский
Процитировано
0
The Journal of Organic Chemistry, Год журнала: 2024, Номер unknown
Опубликована: Дек. 2, 2024
We report herein that three facile rearrangements of epoxy ketones can be employed for the efficient and practical synthesis cephalotaxine, parent member family Cephalotaxus alkaloids. The Meinwald rearrangement ketone (90%) was used preparation dense functional groups in cyclopentane ring cephalotaxine. A novel acid-catalyzed umpolung SN2′ Wharton transposition reaction were also developed to synthesize Mori intermediate via key azaspiro allylic alcohols a stereodivergent manner.
Язык: Английский
Процитировано
0
Tetrahedron Letters, Год журнала: 2024, Номер 155, С. 155437 - 155437
Опубликована: Дек. 31, 2024
Язык: Английский
Процитировано
0