Making Molecular Models

Make molecular models of the three isomers of C5H12... 

The fact that all of these structural for mulas represent the same substance can be clearly seen by making molecular models... 

Make molecular models of c/s and trans 1 2 dimethylcy clopropane and compare their strain energies... 

Write structural formulas or make molecular models for the most stable conformation of each of the following compounds... 

Two stereoisomers of bicyclo[3 3 OJoctane are possible Make molecular models of both and determine which is more stable... 

Make molecular models of (f) and (Z) cyclooctene and compare their H—C=C—H dihedral angles... 

The stereoselectivity of elimination of 5 bromononane on treatment with potassium ethox ide was described in Section 5 14 Draw Newman projections or make molecular models of 5 bromononane showing the conformations that lead to cis 4 nonene and trans 4 nonene respec tively Identify the proton that is lost in each case and suggest a mechanistic explanation for the observed stereoselectivity... 

Compound A undergoes catalytic hydrogenation much faster than does compound B Why" Making molecular models will help... 

There are two products that can be formed by syn addition of hydrogen to 2 3 dimethylbi cyclo[2 2 1] 2 heptene Write or make molecular models of their structures... 

Draw Fischer projections or make molecular models of the four stereoisomeric 3 ammo 2 butanols and label each erythro or threo as appropriate... 

Make molecular ) models of the reac tant and both prod ucts shown in the equation... 

Make molecular models of the two chair conformations of cis 1 tert butyl 4 phenyl cyclohexane What is the strain energy calculated for each conformation by molecular mechanics Which has a greater preference for the equatorial onentation phenyl or tert butyD... 

Verify by making molecular models that the bonds to sulfur are... 

You might find it ) helpful to make molecular models of all the C6H14 isomers. 

Draw three-dimensional representations or make molecular models of... 

Verify, by making molecular models, that the bonds to sulfur are arranged in a trigonal pyramidal geometry in sulfoxides and in a tetrahedral geometry in sulfones. Is phenyl vinyl sulfoxide chiral What about phenyl vinyl sulfone ... 

Because of their cyclic structures, cycloalkanes have two faces as viewed edge-on, a "top" face and a "bottom" face. As a result, isomerism is possible in substituted cycloalkanes. For example, there are two different 1,2-dimethyl-cyclopropane isomers, one with the two methyl groups on the same face of the ring and one with the methyls on opposite faces (Figure 4.2). Both isomers are stable compounds, and neither can be converted into the other without breaking and reforming chemical bonds. Make molecular models to prove this to yourself. 

Cvclodecene can exist in both cis and trans forms, but cyclohexene cannot. Explain. (Making molecular models is helpful.)... 

Evidence that cleavage of 1,2-diols by HIO4 occurs through a five-membered cyclic periodate intermediate is based on kinetic data—the measurement of reaction rates. When diols A and B were prepared and the rates of their reaction with HIO4 were measured, it was found that diol A cleaved approximately 1 million times faster than diol B. Make molecular models of A and B and of potential cyclic periodate intermediates, and then explain the kinetic results. 

Dehydration of t/ri s-2-methylcyclopentanol with POCl3 in pyridine yields predominantly 3-methylcyclopentene. Is the stereochemistry of this dehydration syn or anti Can you suggest a reason for formation of the observed product (Make molecular models )... 

Each isomer is the mirror image of the other and they are known as optical isomers or enantiomers. But all molecules have mirror images, yet they do not all exhibit optical isomerism. What makes lactic acid different is that its two isomers are non-superimposable. You should make molecular models of these optical isomers to convince yourself that one isomer cannot be superimposed on the other. 

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