Stereoselective Total Synthesis of Nimbolide
David B Ryffel1,2, Peter C Ryffel2, Matteo Martinelli3
1Department of Chemistry, Rice University, Houston, Texas 77005, United States.
None:
A stereoselective total synthesis of nimbolide has been achieved in a convergent, 11-step sequence from α-methyl-(R)-carvone. The strategy relied on a stereoselective palladium-catalyzed borylative Heck cyclization where the A-ring of the nimbolide core was constructed while simultaneously performing oxidation at C(28). Selective manipulations delivered a fully decorated decalin moiety on large scale. Then, a stereoretentive etherification reaction brought together two fragments and forged the critical C-O bond with high selectivity. Finally, a regioselective radical cyclization and late-stage lactonization completed the total synthesis of nimbolide.
More Related Videos
11:04Preparation of Enantiopure Non-Activated Aziridines and Synthesis of Biemamide B, D, and epiallo-Isomuscarine
Published on: June 13, 2022
07:30A Direct, Regioselective and Atom-Economical Synthesis of 3-Aroyl-N-hydroxy-5-nitroindoles by Cycloaddition of 4-Nitronitrosobenzene with Alkynones
Published on: January 21, 2020
Related Concept Videos
01:29Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry
02:36Regioselectivity and Stereochemistry of Hydroboration
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn...
02:23SN2 Reaction: Stereochemistry
If the substrate is an achiral molecule at the α-carbon, the inversion of configuration is not...
01:28Diels–Alder Reaction Forming Cyclic Products: Stereochemistry
02:15SN1 Reaction: Stereochemistry
In the first step of an SN1 reaction, the bond between the electrophilic carbon and the leaving group ionizes to generate the carbocation intermediate. The second step of the mechanism is the nucleophilic attack.
In the formed carbocation, the positively charged carbon is sp2 hybridized with a trigonal planar geometry. As all the three substituents lie on the same plane, a plane of symmetry for the...
02:05Prochirality