Chem 241a 1nd Edition Lecture 5Outline of Last Lecture I. Continuation of nomenclatureII. Simple branch compoundsIII. More complicated branched compoundsIV. Naming cycloalkanesOutline of Current Lecture I. Conforming IsomersII. Conformation of CycloalkanesCurrent LectureI. Conforming Isomersa. Energy forms of the same molecule that can be interconverted by simple bond rotationsi. These have the SAME MOLECULAR FORM and SAME CONNECTIVITY, but different bonding schemesii. In order to see their conformities, we must be able to picture them in 3D This is how we get to Newman Projectionsb. Newman Projections: describe 3D bondingi. How we are looking at these molecules is from a side perspective, so one of the carbons are hidden behind the other (follow the red arrow)ii. Newman projections are drawn using two Y shaped lines and a circle. The front Y represents the CH3 group in front; the circle represents the bond between the two carbons. The back upside-down Y (the one that is in pieces) represents the back carbon and their CH3 groupsiii. The angle between a group in the front carbon and a group on the back carbon is called a dihedral angle (θ)→ If θ is 0°, the two groups are eclipsed of each other→ If θ is 60°, the two groups are gauche of each other→ If θ is 180°, the two groups are anti of each otherc. There are two types of conformers: i. Staggered-in between the spacesii. Eclipsed-right behind each otherd. Types of conformers of ethane 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.e. Conformers of Butane i. The top row are the staggered conformations of butane The gauche confirmations are the same energy as each other and have more energy than the anti staggeredii. The second row are the eclipsed conformations The two rightmost conformations are the same energy, but less energetic than “The Eclipsed” confirmation (the leftmost conformer)iii. However, the eclipsed confirmations are higher energy than the staggeredconfirmationsiv. This can be represented on a potential energy diagram:v. The hills are eclipsed, while the wells are staggeredII. Conformation of Cycloalkanesa. Cyclopropane:i. Contains a lot of angle strain due to the 60° anglesii. Contains torsional strain (where the electrons are as close as possible)iii. They also contain steric strain (where two big groups such as CH3 or CH2CH3)b. Cyclobutane:i. Also contains angle strain (90°)ii. Contains torsional strainiii. Contains steric strainc. Cyclopentane:i. Less angle strain due to more carbonsii. Exists as puckering because they start to bendiii. This is the first conformational cycloatom with mobilityd. Cyclohexane:i. Strain free as much as an alkaneii. Becomes staggered and rarely