CH 220 1st Edition Lecture 16Outline of Current Lecture I. Gargantulide AII. OrganohalidesIII. Naming Alkyl HalidesIV. Preparing Alkyl HalidesV. Substitution vs. EliminationVI. Nucleophilic substitution reactionsVII. Substitutions: The SN2 reactionCurrent LectureI. Gargantulide ABiggest organic molecule, composed of a 52 carbon ringNaturally occurringVery powerful antibiotic, but also very poisonousMore than half of the carbons are chiralII. OrganohalidesOrganic compound containing at least one carbon-halogen bond (C-X), normally containsseveralFire resistant solvents (don’t ever burn), inert, stableRefrigerantsUsed in pharmaceuticals (Cl, Br, F) & precursorsSplenda – substitute in Cl Body doesn’t recognize it as a sugar and so doesn’t digest itRetains some of the basic properties (i.e. sweetness)III. Naming Alkyl HalidesTriple bond needs to be in the parent chainNumber from end nearest any substituent (halogen or alkyl – neither have priority)If two halides or alkyls are equally distant from the ends of the chain, work alphabeticallyi.e. 2-bromo-5-methylhexaneThese 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.IV. Preparing Alkyl HalidesHydrohalogenation & Halogenation are usedPreparing alkyl halides with alcohol is fast and effective when using tertiary alcoholsThis is a substitution reactionV. Substitution vs EliminationSubstitution keeps the single bond between carbonsElimination makes a double bondVI. Nucleophilic substitution reactionsRegardless of mechanism, the overall changes during a nucleophilic reaction are the sameNucleophile ( Nu: or Nu:- ) reacts with substrate (R-X)Substitutes for the leaving group ( X:- )To yield a new product (R-Nu)Nucleophiles have a negative charge or a negative characteristic (i.e. lone pairs)VII. Substitutions: The SN2 reactionThese 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.The transition state occurs in the mechanism but it is not detectable in product or reactant – it is the imagined stepIn the above reaction:OH is the nucleophile, CH3Br is the substrate, Cl- is the leaving group It is a concerted mechanism – it happens at the same time (check out the animation videos uploaded to moodle)The shape of the molecule will change during the reaction, because OH- comes in from the back and so Cl- will leave from the front. This means that if the reaction starts with a chiral S molecule, it will end in a chiral R molecule and vice versa.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