Preparation of chiral diphenyl substituted polyether-diester compounds

Abstract

A new series of chiral polyether-diester ligands has been prepared by reacting racemic and chiral diphenyl-substituted tetraethylene glycols with diglycolyl chloride (5 and 6), 2,5-furandicarbonyl chloride (7 and 8), 2,6-pyridinedicarbonyl chloride (9-12), and 4-methoxy-2,6-pyridinedicarbonyl chloride (13). The chiral diphenyl-substituted tetraethylene glycols were prepared from the di-, (S)-, and (R)-mandelic acids.

Chiral recognition by the S,S and R,R enantiomers of dimethyldioxopyridino-18-crown-6 as measured by temperature-dependent proton NMR spectroscopy in CD2Cl2, titration calorimetry in methanol at 25.degree., and selective crystallization

“…19-22* a (a) NaH, THF, (b) CH2=C((CH3)3SiCH2)CH2OMs,9 (c) CH3I, AgCIO,, (d) (CH3)3CC0C1, AgC104, (e) yields for sequences are 89%, 85%, 90%, and 90%, respectively. silylation of the intermediate diradical cation intermediates, and (3) provide by diradical cyclization pyrrolidine ring systems (17 and 18) with attractive exo-or endo-cyclic olefin functionality (Scheme III). The results from investigation of the IV-[ [ (trimethylsilyl)methyl] allyl]iminium salts 19-22 illustrate the potential of strategies based on the sequence 15 -17.…”

Enantiomeric Recognition of Organic Ammonium Salts by Chiral Pyridino- 18-Crown-6 Ligands: A Short Review

“…As can be seen in Figure 1, the pyridino-crowns are of five types -[] diester-crowns (1-9 and 13), bisamido-crowns (10-12), a thiono diester-crown (14), bis(thionoamido)-crowns (15)(16)(17), and the crown ethers (18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31). Table I) .…”

Electron transfer initiated iminium salt photospirocyclization methodologies. Model studies for harringtonine alkaloid synthesis

“…The iV-prenyl side chain was incorporated into the systems selected for initial study in order to guarantee efficient electron transfer between the olefin and excited iminium salt groups.4 Irradiation of methanolic solutions of iminium perchlorates 5-8, conducted in a preparative apparatus with light of > 240 nm, followed by aqueous base treatment of the crude photolysate and chromatographic purification on alumina or silica gel, afforded the spirocyclic amines 9-12 as mixtures of C-8 and C-9 epimers in the yields ranging from 19% to 31%. The O-protonated salt 14, prepared in situ by treatment of a methanolic solution of the corresponding enaminone with 0.1 N (3) Smith, C. R.; Mikolajczak, K. L.; Powell, R. G. "Medicinal Chemistry. Anticancer Agents Based on Natural Product Models"; Cassady, J. M., Douros, J. D., Ed.…”