Chair cyclohexane

Figure A3.6.11. Viscosity dependence of transmission coefficient of the rate of cyclohexane chair-boat inversion in liquid solution (data from [100]).

Practice drawing cyclohexane chairs oriented in either direction... 

Pr actice drawing cyclohexane chair s oriented in either dir ection. 

The chair conformation of cyclohexane has many consequences. We ll see in Section 1.1.9, for instance, that the chemical behavior of many substituted cyclohexanes is influenced by their conformation. In addition, we ll see in Section 2S.5 that simple carbohydrates such as glucose adopt a conformation based on the cyclohexane chair and that their chemistry is directly affected as a result. 

Fig. 7.1 Symbolic drawings of cyclohexane chair and boat conformations in two dimensions using different line thickness and wedge symbols.

Fig. 3. Symmetry elements and torsion angles of cyclohexane (chair conformation) and cyclodecane (stable BCB-conformation)...

Note that the wedges and bold bonds help to show how we are looking at the cyclohexane chair. In practice, particularly to speed up the drawing of structures, we tend to omit these. Then, by convention, the lower bonds... 

Cineole provides an example of a bridged ring system. The essence of this problem is to spot that we cannot bridge the opposite carbons of a cyclohexane chair conformation it is necessary to have the cyclohexane in a boat form. Then the answer is readily obtained. 

This can be achieved only in favorable cases, e.g., by differences in stcric hindrance at both reactive sites in compound 1 or by annulating the epoxide to a cyclohexane chair with locked conformation (principle of diaxial attack4). 

Interestingly, trimer was formed through secondary bonds between the iodine(III) and the two oxygen atoms (01 and 02) in the solid state of 1-alkynyl-lA3,2-benziodoxol-3(lH)-one 142 (Fig. 8) [225]. In the solid state the ethynyl substituent occupies an axial position of the cyclohexane chair conformer. 

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