Chem 241a-1st Edition Lecture7 Outline of Last Lecture I. Conformations of Cyclohexanes (continued)II. How to Draw Chair CyclohexanesIII. How to Draw Newman Projectionsa. Monosubstituted cyclohexanesb. Disubstituted cyclohexanei. Stereochemistry ii. Conformational EnergyOutline of Current Lecture I. Continuation of chair conformers of cyclohexanesII. Stereochemistry (Chapter 5)a. Chiralb. Achiralc. Enantiomersd. DiastereoimersCurrent LectureI. Continuation of chair conformers of cyclohexanesa. Ex: Which is the most stable conformer of cis-1-ethyl-2-methylcyclohexane?b. The second one is more stable because the larger group (ethyl) is equatorialc. NOTE: a trans-1-2 disubstituted (a ring with two groups attached) cyclohexane is always more stable than a cis-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. Ex: 1,3-disubstituted cyclohexane:e. The cis in the equatorial position is the most stable because both methyl’s can bein that position over the transKEEP IN MIND: - Trans 1,2 – more stable > cis because it can have 2 equatorial positions (cis contains 1 equatorial and 1 axial)- Cis 1,2 – more stable > trans because it can have 2 equatorial positions (trans contains 1 equatorial and 1 axial)- Trans 1,4 – more stable > cis because it can have 2 equatorial positions (cis contains 1 equatorial and 1 axial)=======================CHAPTER 5=========================II. Stereochemistrya. Chiral – an object that has a non-superimposible mirror image – this means that an object, if it were turned around in the mirror it would be different from the original image. The most famous example is your hand. In a mirror, the hand is the same. But if you turn your hand (the right one) in the mirror around and overlapped the two pictures, one would be the right hand and the mirror would turn into the left.b. Non-chiral – an object that has a superimposible mirror image – this means that the mirror image can be turned around and would be exactly the same figure on top of each other – much like a chair without arms. The chair in the mirror wouldbe a chair facing back at it. If we took the chair that is on the mirror, turned it around, then we could stack it on top of the otherStereoisomer – same molecular formula, same connectivity, different in spacial arrangements and cannot be changed by simple bond movement, therefore breakage must occur*Steroisomers can be broken up into two groups:Molecules can be chiral or achiral too based on their chiral centers/stereocenters/stereogenic centers – a sp3 carbon with four DIFFERENT groups attachedIII. Enantiomers (Chiral molecules)a. Ex. IV. Diastereomers (To be covered next