Das, Pradipta published the artcileDramatic Effect of γ-Heteroatom Dienolate Substituents on Counterion Assisted Asymmetric Anionic Amino-Cope Reaction Cascades, Application In Synthesis of 1468-83-3, the main research area is counterion assisted anionic cascade Mannich reaction Cope rearrangement cyclization.
We report a dramatic effect on product outcomes of the lithium ion enabled amino-Cope-like anionic asym. cascade when different γ-dienolate heteroatom substituents are employed. For dienolates with azide, thiomethyl, and trifluoromethylthiol substituents, a Mannich/amino-Cope/cyclization cascade ensues to form chiral cyclohexenone products with two new stereocenters in an anti-relationship. For fluoride-substituted nucleophiles, a Mannich/amino-Cope cascade proceeds to afford chiral acyclic products with two new stereocenters in a syn-relationship. Bromide- and chloride-substituted nucleophiles appear to proceed via the same pathway as the fluoride albeit with the added twist of a 3-exo-trig cyclization to yield chiral cyclopropane products with three stereocenters. When this same class of nucleophiles is substituted with a γ-nitro group, the Mannich-initiated cascade is now diverted to a β-lactam product instead of the amino-Cope pathway. These anionic asym. cascades are solvent- and counterion-dependent, with a lithium counterion being essential in combination with ethereal solvents such as MTBE and CPME. By altering the geometry of the imine double bond from E to Z, the configurations at the R1 and X stereocenters are flipped. Mechanistic, computational, substituent, and counterion studies suggest that these cascades proceed via a common Mannich-product intermediate, which then proceeds via either a chair (X = N3, SMe, or SCF3) or boat-like (X = F, Cl, or Br) transition state to afford amino-Cope-like products or β-lactam in the case of X = NO2.
Journal of the American Chemical Society published new progress about Chiral auxiliary. 1468-83-3 belongs to class benzothiophene, name is 3-Acetylthiophene, and the molecular formula is C6H6OS, Application In Synthesis of 1468-83-3.
Referemce:
Benzothiophene – Wikipedia,
Benzothiophene | C8H6S – PubChem