Gary Molander completed his undergraduate studies in chemistry at Iowa State University under the tutelageo fP rofessor Richard C. Larock. He earned his PhD at Purdue University with Professor HerbertC. Brown and undertook postdoctoral training with Professor Barry M. Trost at the University of Wisconsin, Madison. He began his academic career at the University of Colorado, Boulder,m oving to the University of Pennsylvaniai n1 999, where he is currently the Hirschmann-Makineni Professor of Chemistry. Scheme 2. Enantioselective photoredox/Ni dual-catalyzed cross-coupling of A) a-trifluoromethyltrifluoroborates and B) a-alkoxymethyltrifluoroborates. Scheme 3. Enantioselective photoredox/Ni dual-catalyzed desymmetrization of A) cyclic meso anhydrides and B) diols. Angewandte Chemie Minireviews Scheme 4. Enantioselective photoredox/Ni dual-catalyzed decarboxylative arylations. Scheme 5. Enantioselective photoredox/Ni dual-catalyzed C(sp 3)-H arylation. Angewandte Chemie Minireviews Scheme 9. Enantioselective photoredox/Ni dual-catalyzed 1,2-carbodifunctionalization of carbamoyl chloride-tethered alkenes. Scheme 10. Mechanism involving photoexcitation of aCu I complex and reductive elimination from Cu III. Scheme 11. Enantioselective C-N cross-couplingoftertiary a-chloroamides with carbazoles and indoles. Scheme 12. Interposing aGiese-type addition prior to formation of the Cu III intermediate enables A) cyanation/fluoroalkylation and B) alkylation/alkynylation or arylation/alkynylationo falkenes. Angewandte Chemie Minireviews Scheme 23. Diastereoselective photoredox/Ni dual-catalyzed 1,2-carbosulfonylationo falkynes.
The biosynthesis of thebaine is based on the regioselective, intramolecular, oxidative coupling of (R)-reticuline. For decades, chemists have sought to mimic this coupling by using stoichiometric oxidants. However, all approaches to date have suffered from low yields or the formation of undesired regioisomers. Electrochemistry would represent a sustainable alternative in this respect but all attempts to accomplish an electrochemical synthesis of thebaine have failed so far. Herein, a regio- and diastereoselective anodic coupling of 3',4',5'-trioxygenated laudanosine derivatives is presented, which finally enables electrochemical access to (-)-thebaine.
A fully
regio- and diastereoselective electrochemical 4a–2′-coupling
of a 3′,4′,5′-trioxygenated laudanosine derivative
enables the synthesis of the corresponding morphinandienone. This
key intermediate is further transformed into (−)-oxycodone
through conjugate nucleophilic substitution for E-ring closure and
[4 + 2] cycloaddition with photogenerated singlet oxygen to accomplish
diastereoselective hydroxylation at C-14. The anodic transformation
provides high yields and can be performed under constant current conditions
both in a simple undivided cell or in continuous flow.
A highly efficient metal-free catalytic system for the aerobic photocyanation of tertiary amines with visible light is reported. The use of air as terminal oxidant offers an improved safety profile compared with pure oxygen, the used compact fluorescent lamp (CFL) light sources are highly economical, and no halogenated solvents are required. This system not only proves to be effective for a wide variety of trialkylamines, pharmaceuticals, and alkaloids but remarkably also allows the lowest catalyst loading (0.00001 mol% or 0.1 ppm) ever reported for an organic dye. Bruylants reactions and C-alkylation/decyanations were performed on the obtained α-aminonitriles to demonstrate the postfunctionalization of complex molecules. The catalytic system is furthermore applied in the short and effective syntheses of the alkaloids (±)-crispine A and the tetraponerines T7 and T8.
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