Advanced Mapping of Optically-Blind and Optically-Active Nitrogen Chemical Impurities in Natural Diamonds

Are lignins optically active?

The accepted derivation of lignins from non(enzymatically)-controlled radical coupling reactions has been recently challenged, and it is relevant to ascertain unequivocally whether lignins are or are not (as normally assumed) optically active. Two approaches were used. First, DFRC (derivatization followed by reductive cleavage) dimers derived from beta-5- and beta-beta-units in pine lignins, wh...

Optically Active Coordination Compounds. Part 50.' 4-Fold Symmetry Axes in Optically Active Complex Ions from Natural Nicotine

Optically active diaryl tetrahydroisoquinoline derivatives.

In (1R,3S)-6,7-dimethoxy-3-(methoxydiphenylmethyl)-1-phenyl-1,2,3,4-tetrahydroisoquinoline, C(31)H(31)NO(3), (I), and (1R,3S)-2-benzyl-3-[diphenyl(trimethylsiloxy)methyl]-6,7-dimethoxy-1-phenyl-1,2,3,4-tetrahydroisoquinoline, C(40)H(43)NO(3)Si, (II), the absolute configurations have been confirmed to be R and S at the isoquinoline 1- and 3-positions, respectively, by NMR spectroscopy experiment...

Synthesis and Reactions of Optically Active Cyanohydrins

Franz Effenberger * . Cyanohydrins have always held a place of importance both as technical products and as reagents in organic chemistry. It is surprising. therefore. that optically active cyanohydrins have been extensively investigated and employed for syntheses relatively recently. This can be explained by the fact that only in the past few years have enzymatic methods made chiral cyanohydri...

Configurational Molecular Glue: One Optically Active Polymer Attracts Two Oppositely Configured Optically Active Polymers

D-configured poly(D-lactic acid) (D-PLA) and poly(D-2-hydroxy-3-methylbutanoic acid) (D-P2H3MB) crystallized separately into their homo-crystallites when crystallized by precipitation or solvent evaporation, whereas incorporation of L-configured poly(L-2-hydroxybutanoic acid) (L-P2HB) in D-configured D-PLA and D-P2H3MB induced co-crystallization or ternary stereocomplex formation between D-conf...