Thermal cycloreversion of 2,2-dimethyl-6 (.omega.-hydroxyalkyl)-4H-1,3-dioxin-4-ones: mono-, di-, and trimeric macrocyclic .beta.-keto lactones by intramolecular trapping of (.omega.-hydroxy)acylketenes
Thermal cycloreversion of 2,2-dimethyl-6 (.omega.-hydroxyalkyl)-4H-1,3-dioxin-4-ones: mono-, di-, and trimeric macrocyclic .beta.-keto lactones by intramolecular trapping of (.omega.-hydroxy)acylketenes
Efficient Organocatalytic Construction of C4-Alkyl Substituted Piperidines and Their Application to the Synthesis of (+)-α-Skytanthine
作者:Shinya Shiomi、Erika Sugahara、Hayato Ishikawa
DOI:10.1002/chem.201503117
日期:2015.10.12
Chiral piperidines which contain an alkyl group at C4 positions are one of the important architectures because it is appeared in several natural products. An efficient protocol for the preparation of C4‐alkyl substituted chiral piperidines using secondary amine catalyzed formalaza [3+3] cycloadditionreaction with aliphatic α,β‐unsaturated aldehydes and thiomalonamate derivatives is reported. In our
A cationic CpRu/halogen/Brønsted acid hybrid catalyst (R cat) with the axially chiral Cl-Naph-PyCOOH ligand (naph = naphthyl, py = pyridine) is highly efficient for dehydrative cyclization of pyrroles to construct 1,2-fused-2-allylated pyrroles that, so far, have not been achieved. The mechanistic study has implied that hydrogen and halogen bonds play a key role for facilitating the R,SRu-catalyzed
Chemo- and Enantioselective Pd/B Hybrid Catalysis for the Construction of Acyclic Quaternary Carbons: Migratory Allylation of <i>O</i>-Allyl Esters to α-<i>C</i>-Allyl Carboxylic Acids
We describe herein the asymmetric synthesis of α-allyl carboxylic acids containing an α-quaternarystereocenter by a chiral hybrid catalyst system comprising palladium and boron complexes. The reaction proceeded through palladium-catalyzed ionization of α,α-disubstituted O-allyl esters for the generation of chiral π-allyl palladium complex as an electrophile, boron-catalyzed enolization of the carboxylate
Thermal cycloreversion of 2,2-dimethyl-6 (.omega.-hydroxyalkyl)-4H-1,3-dioxin-4-ones: mono-, di-, and trimeric macrocyclic .beta.-keto lactones by intramolecular trapping of (.omega.-hydroxy)acylketenes
作者:Chixu Chen、Erik K. Quinn、Marilyn M. Olmstead、Mark J. Kurth