In nothing flat: The title salts, having planar nitrogen centers, were utilized successfully as phase‐transfer catalysts for asymmetric Michael reactions of tert‐butyl glycinate benzophenone Schiff base with vinyl ketone and chalcone derivatives, thus providing excellent levels of diastereo‐ and enantiocontrol (see scheme).
The synthesis of Pd(OTf)(2)·2H(2)O is described. This was used to generate two different types of chiral dicationic palladium complexes for highly enantioselective addition of aromatic amines to α, β-unsaturated conjugate alkenes ([(R-BINAP)Pd(OH(2))(2)][OTf](2) and [(R-BINAP)Pd(μ-OH)](2)[OTf](2)). The resulting optically active N-arylated β-amino acid derivatives are valuable synthetic intermediates for the synthesis of biologically active molecules and peptidomimetics. The reaction of (2E)-but-2-enoylcarbamate and aniline is shown as an example of the use of these catalysts for enantioselective aza-Michael addition. For the preparation of palladium(II) triflate, the time scale is 20 h 50 min, plus 5 h 15 min for the monomeric complex and plus 6 h 45 min for the dimeric complex.
A family of new chiral zwitterionic phosphorus-containing heterocycles (zPHC) have been derived from methylene-bridged bis(imidazolines). These structures were unambiguously determined, including single-crystal XRD analysis for two compounds. The stability, acid/base and electronic properties of these dipolar phosphorus heterocycles were subsequently investigated. zPHCs can be successfully employed as a new class of chiral solvating agents for the enantiodifferentiation of chiral carboxylic and sulfonic acids by NMR spectroscopy. The stoichiometry and binding constants for the donor-acceptor complexes formed were established by NMR titration methods.
The first asymmetric synthesis of a synthetic cannabinoid levonantradol was accomplished, and the 3-D solution structure of its core architecture was confirmed by NMR and computational methods.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.