An asymmetric formal synthesis of azadirachtin, a potent insect antifeedant, was accomplished in 30 steps to Ley's synthetic intermediate (longest linear sequence). The synthesis features: 1) rapid access to the optically active right-hand segment starting from the known 5-hydroxymethyl-2-cyclopentenone scaffold; 2) construction of the B and E rings by a key intramolecular tandem radical cyclization; 3) formation of the hemiacetal moiety in the C ring through the α-oxidation of the six-membered lactone followed by methanolysis.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1002/anie.201507935 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Asymmetric Organocatalytic 1,6-Conjugate Addition of Alkynyl 8-Methylenenaphthalen-2(8)-one Formed In Situ: Synergistic Construction of Axial and Central Chirality.
Org Lett
January 2025
Taizhou Research Institute, Southern University of Science and Technology, Taizhou 318014, Zhejiang, China.
Organocatalytic enantioselective formal nucleophilic substitution reactions of α-(2-hydroxynaphthalen-8-yl)propargyl alcohols with 1-(1-indol-3-yl)naphthalen-2-ols have been established for the first time. With the aid of a suitable chiral phosphoric acid, alkynyl 8-methylenenaphthalen-2(8)-one was formed in situ from the corresponding α-(2-hydroxynaphthalen-8-yl)propargyl alcohol, followed by enantioselective 1,6-conjugate additions of 1-(1-indol-3-yl)naphthalen-2-ols to afford a number of enantioenriched (,)-2,3-disubstituted indoles in 50-80% yields with 81-93% ee and (,)-2,3-disubstituted indoles in 18-40% yields with 79-96% ee. Notably, these nucleophilic substitution products were characterized by the presence of functional groups, including indole, naphthol, and alkynyl units, while exhibiting both axial and central chirality.
View Article and Find Full Text PDFEnantioselective Heck/Tsuji-Trost reaction of flexible vinylic halides with 1,3-dienes.
Nat Commun
January 2025
College of Chemistry and Life Science, Advanced Institute of Materials Science, Changchun University of Technology, Changchun, P. R. China.
The enantioselective domino Heck/cross-coupling has emerged as a powerful tool in modern chemical synthesis for decades. Despite significant progress in relative rigid skeleton substrates, the implementation of asymmetric Heck/cross-coupling cascades of highly flexible haloalkene substrates remains a challenging and and long-standing goal. Here we report an efficient asymmetric domino Heck/Tsuji-Trost reaction of highly flexible vinylic halides with 1,3-dienes enabled by palladium catalysis.
View Article and Find Full Text PDFThe extinction burst: Effects of reinforcement magnitude.
J Exp Anal Behav
January 2025
Utah State University, Logan, UT, USA.
The extinction burst is an increase in an operant behavior early in the transition to extinction. A matching-law-based quantitative theory suggests that it results from the elimination of competition from reinforcement-related behavior that accompanies the transition to extinction. This experiment examined the effects of reinforcement magnitude on the extinction burst with rats.
View Article and Find Full Text PDFExploring how structural forms of power shape the training of intraprofessional collaboration between family physicians and specialty physicians in outpatient workplace settings.
Med Educ
January 2025
The Institute for Education Research, University Health Network, Toronto, Canada.
Introduction: Intraprofessional collaboration between family physicians (FPs) and specialist physicians (SPs) is posited to improve patient outcomes but is hindered by power dynamics. Research informing intraprofessional training on hospital wards often conceptualizes power at an interactional level. However, less is known about how social structures make these power dynamics possible.
View Article and Find Full Text PDFSecupyritines A-C, Three Natural Propellane Securinega Alkaloids: Structure Elucidation and Total Synthesis Based on Biogenetic Building Blocks.
Angew Chem Int Ed Engl
January 2025
State Key Laboratory of Bioactive Molecules and Druggability Assessment, Jinan University, Guangzhou, 510632, China.
Secupyritines A-C are unique polycyclic Securinega alkaloids isolated from medicinal plant Flueggea suffruticosa. They feature a distinctive 6/6/6/5/6 fused pentacyclic ring system with a highly strained 2-oxa-6-aza[4.4.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!