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• 37031-29-1 (-)-dimethy-2,3-O-isopropylidene-L-tartrate 
• 13139-86-1 4-methoxyphenyl magnesium bromide 
• 59779-75-8 diethyl (4R,5R)-2,2-dimethyl-1,3-dioxolane-4,5-dicarboxylate 
• 104-92-7 1-bromo-4-methoxy-benzene 

Relevant academic research and scientific papers

A quaternary phosphonium salt compound and its preparation method

The present invention discloses a quaternary phosphonium salt compound and a preparation method thereof. The method uses cheap and readily available L-tartaric acid as the raw material, and conducts carboxyl esterification, hydroxyl protection, Grignard reaction, azide substitution, azide reduction and final reaction with phosphorus pentachloride, so as to obtain the quaternary phosphonium salt compound. The quaternary phosphonium salt compound is a novel Bronsted acid catalyst (a hydrogen bond donor catalyst), and can be used in the catalysis of asymmetric Mannich reaction, Michael reaction and Henry reaction.

Ni-Catalyzed Asymmetric Cycloisomerization of Dienes by Using TADDOL Phosphoramidites

A library of α,α,α,α-tetraaryl-1,3-dioxolane-4,5-dimethanol (TADDOL)-based phosphoramidites has been synthesized and applied in the Ni-catalyzed cycloisomerization of different dienes. Through the systematic variation of the three structural motifs of the

Enantioselective gold catalysis: Opportunities provided by monodentate phosphoramidite ligands with an acyclic TADDOL backbone

(Chemical Equation Presented) The tail makes the difference: Removing the isopropylidene acetal unit from well-known TADDOL ligands improved the performance of the derived phosphoramidite ligands in asymmetric gold catalysis (see scheme; Ts=4-toluenesulfonyl). X-ray crystallography showed that the binding pocket has an effective three-fold symmetry, with through-space interactions between the arene rings of the ligand and the gold center.

Design and evaluation of inclusion resolutions, based on readily available host compounds

Resolution of enantiomers through selective crystallisation of diastereomeric inclusion compounds can extend the scope of traditional racemate resolution beyond salt forming compounds. To assess the practical value of this approach the literature was carefully screened and promising results were checked. Also an extensive range of new inclusion hosts suitable for resolution processes, derived from simple hydroxy- and amino acids were prepared and tested. Several techniques, including the Dutch Resolution approach utilizing mixtures of resolving agents, were applied. Over 70 potential resolving agents were tested in combinations with 34 racemates (over 100 racemates if literature results are included). Reproducibility of literature results was found to be problematic. Also the number of successful new resolutions found was very limited: only two efficient resolutions out of 1200 combinations of racemate and resolving agent tested in over 10.000 experiments! Crystal studies of representative combinations of resolving agents and inclusion compounds revealed some of the causes for the low rate of success in inclusion resolution. Compared to diastereomeric salts, the absence of strong electrostatic interactions substantially reduces the probability of forming crystals including both components. Molecular structure features allowing formation of intricate intramolecular and intermolecular H-bond networks were found to be responsible for inclusion crystal formation, and for the quality of the ensuing resolution through selective diastereomer crystallisation, in the successful cases. Whereas diastereomeric salt resolution continues to be of scientific and industrial interest, inclusion resolution should be viewed as of very limited scope; useful in specific instances, but lacking the wide applicability of classical resolution. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.

Preparation and Cationic Rearrangements of ortho- and para-Methoxy-TADDOLs

(R,R)-α,α,α',α'-Tetra(2-methoxy- and 4-methoxyphenyl)-1,3-dioxolane- and -2,2-dimethyl-1,3-dioxolane-4,5-dimethanols are prepared from the corresponding tartrate acetal or ketal and Grignard reagents.The ortho-methoxy derivatives have an unusual conformation in the crystalline state (determined by X-ray analysis) and in solution (derived from chiroptical measurements).Structural similarities with the TADDOL bearing six phenyl groups are discussed, and the crystal structure of a hydrogen-bonded clathrate of this TADDOL with piperidine is also reported.Under acidicconditions the 4-methoxy-TDDOLs undergo cyclisation to a tetrahydrofuran or to a dihydro-naphthalene derivative, which in turn rearranges to 6-methoxy-1,3,4-tris(4-methoxyphenyl)naphth-2-yl acetate.The structures of these TADDOL "decomposition" products are proved by NMR and X-ray analysis.Wagner-Meerwein rearrangement, aromatization, carbocations, X-ray structure of chiral ligands, TADDOLs, - new methoxy derivatives, - crystal structure, - NMR analysis, optical comparison and conformation of TADDOLs