Stereomers, conformational

Spin-spin coupling in nmr, 242 Spontaneous reaction, 36 Stability, heat of combustion, 90 of radicals, 61 resonance, 24 Staggered conformation, 51 Stereoisomers, 69 Stereomers, conformational, 80 Stereoselective reactions, 91 Steric strain, 54, 126 Stilbene, 218 Strain, torsional, 54, 167 Structure of benzene, 189 cyclooctatetraene, 195 Substitution, ally lie, 105 in arenes, 205 in naphthalene, 213 nucleophilic aromatic, 215 ... 

The unsymmetrical diene ligands in 85b and 85c may form two dia-stereomers with the less substituted double bond in the cis or trans configuration with respect to the Mo—C a bond. For 85b, only the isomer with the less substituted double bond cis to this bond is found. Compound 85c forms both isomers, but the cis isomer is distinctly preferred. In contrast with the fluxional >j2-diene complexes 84a-84c, compounds 85a-85c do not show temperature-dependent H-NMR spectra for the //4-diene ligands. However, this does not disprove a hindered rotation of the f/4-diene ligands when one of the two conformers (o or u) is energetically more favored than the other. 

Chiral centers, more than one, lljf Chiral stereomer, 69 Cholesterol, chirality in, 81 Cinnamaldehyde, 328 Cis-trans interconversion, 111 Cis-trans isomerism, in cyclic compounds, 163 Claisen condensation, 394 rearrangement, 439 Cleavage, oxidative, 117 Clemmensen reduction, 219, 311 Coenzyme A, 354 Collins reagent, 264 Collision frequency, 39 Configuration, 72 relative, 76 Conformation, 51 Conformational diastereomers, 78 enantiomers, 78 stereomers, 78... 

The C3 symmetry of the cup-lilie trimers indicates that they are chiral typically being formed as a racemate. In some cases, the cups are resolvable via suitable dia-stereomers. as the enantiomers are somewhat stable to racemization via conformational inversion of the nine-membered cyclophane ring (AG 298 = 110-1 i5 kJ/mol). Chirality in the cup-shaped units implies that two types of cryptophanes exist Joining two cups of opposite... 

---