Draw the lowest energy conformation adopted by each of the following molecules :
(a) cis-1,3-dimethylcyclohexane (b) cis-1-fluoro-2-isopropylcyclohexane
(c) trans-1-bromo-4-methylcyclohexane (d) trans-3-tert-butylcyclohexanol

Question

Draw the lowest energy conformation adopted by each of the following molecules :

(a) cis-1,3-dimethylcyclohexane (b) cis-1-fluoro-2-isopropylcyclohexane

(c) trans-1-bromo-4-methylcyclohexane (d) trans-3-tert-butylcyclohexanol

TestHub · Accepted Answer

(a) cis-1,3 can be diequatorial - both methyl groups equatorial :

structure

(b) cis-1,2 is always axial-equatorial; the larger isopropyl group takes the equatorial position and F goes axial :

structure

(c) trans-1,4 can be diequatorial - both substituents equatorial :

structure

(d) trans-1,3 is always axial-equatorial; the much larger tert-butyl group insists on the equatorial position, forcing OH axial :

structure

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