Chem 241a-1st Edition Lecture6 Outline of Last Lecture I. Conforming IsomersII. Conformation of CyclohexanesOutline of Current Lecture I. Conformations of Cyclohexanes (continued)II. How to Draw Chair CyclohexanesIII. How to Draw Newman Projectionsa. Monosubstituted cyclohexanesb. Disubstituted cyclohexanei. Stereochemistry ii. Conformational EnergyCurrent LectureI. Conformations of Cyclohexanes (continued)a. The most commonly adopted form is the chair formi. This form is completely staggered and the most stable conformer of cyclohexaneb. The second form of conformations is the boat conformeri. This is less stable than the chair because two of the carbons have eclipsedformations and steric overlap occursII. How to draw chair cyclohexanesa. First draw the parallel end lines of the chair conformer (refer above)b. Second draw the parallel lines that connect the twoc. Then add the groupsi. the groups that go straight up or straight down are called the axial substituentii. the groups that go to the side are called the equatorial substituents (the right three go to the right, the left three go to the left)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.d. For every cyclohexane there are TWO conformersi. When these conformers exhibit ring flips, the axial becomes equatorial and the equatorial becomes axiale. Monosubstituted cxyclohexanes-a cyclohexane with only one odd groupattachedi. Ex: methylcyclohexane: the methyl can either be axial orequatorialii. The axial methylcyclohexane contains diaxial interaction containssteric strain, but the equatorial form relieves this steric strain (notice the axial’s are close together, yet the equatorial’s are spread out away from each other)iii. The bigger the substituents, the more that one wants to be equatorialSubstituent % Equatorial (How much it wants to beequatorial)Methyl 95Isopropyl 97Tertbutyl 99.99f. Disubstituted cyclohexanes-cyclohexanes with two substitutantsi. These had two related but separate issuesg. Stereochemistry – which side of the ring are the groups relative to one anotheri. These have the same molecular formula, the same connectivity, but different spacial arrangements; they cannot be interconverted by bond rotationh. Conformational energy – each stereoisomer is a different cyclohexane compoundand each has two conformations (as above)i. Trans is more stable than cis because of the two methyls that can becomeequatorial, and almost never expresses axial formationsii. The highest energy has a blue circle, the two middle energies has a red circle, and the lowest energy has a green circle around itIII. Newman projections with cyclohexanes-looking down two different bonds opposite of each