Unprecedented stereoselectivity in the addition of organoiron(II) reagents to cyclohexanone derivatives
作者:Manfred T. Reetz、Stephan Stanchev
DOI:10.1039/c39930000328
日期:——
Various organoiron(II) reagents undergo Grignard-type additions to substituted cyclohexanone derivatives, C–C bond formation occurring stereoselectively from the equatorial direction (97–100% selectivity).
Ligand effects on diastereoselective addition of organocerium reagents to aldehydes and cyclic ketones
作者:Nicholas Greeves、Lisa Lyford、J.Elizabeth Pease
DOI:10.1016/s0040-4039(00)76533-6
日期:1994.1
A new class of chiral dialkoxy- and diaryloxyorganocerium reagent has been prepared and the diastereoselectivity of carbonyladdition reactions has been compared with that of conventional organoceriumreagents.
Thermoreversible gelation of organic liquids by arylcyclohexanol derivatives Synthesis and characterisation of the gels
作者:Charles M. Garner、Pierre Terech、Jean-Jacques Allegraud、Brian Mistrot、Phuc Nguyen、Arnaud de Geyer、Daniel Rivera
DOI:10.1039/a801922c
日期:——
A variety of organic liquids can be immobilised using certain 4-tert-butyl-1-arylcyclohexanol derivatives (BACOl). Only the isomers with axial aryl groups are active as gelling agents. The BACOl–hydrocarbon systems have been characterised with respect to their rheological properties under shear. The gels are viscoelastic solids with high elastic shear moduli (G′≈70350 Pa at C≈2.2 wt.% in dodecane) and high yield stresses (σ≈620 Pa). A 3D network with high cohesive energy and long lifetimes of the related structures is in thermal equilibrium with the surrounding solution. Diffraction experiments have characterised the crystallinity of the gel networks made up of assemblies of bimolecular BACOl associations (d≈14.3 Å). Xerogels exhibit a mesomorphic organisation with a 76 Å repeating unit. Phase diagrams have been determined as a function of the solvent and gelator types and the related thermodynamic parameters were deduced. IR spectroscopy has demonstrated that H-bonding is responsible for the aggregation of the BACOl molecules.