I. Introduction to alkyl halides types of organic halides, where alkyl halides are found, preparation, spectroscopy, reactivity, nomenclatureII. Substitution reactions of alkyl halides Introduction Mechanisms Which substitution reaction? Strong vs Weak Nucleophiles Products Stereochemistry Rate Laws Rearrangements Solvents Exclusion of aryl halides, vinyl halides, and acid chlorides Summary of Substitution ReactionsIII. Synthesis Using Substitution ReactionsLearning Guide for Chapter 9 - Alkyl Halides II. Introduction to alkyl halidesTypes of organic halidesWhat is the purpose of categorizing organic halides into different groups?Label the following compounds as alkyl halides, aryl halides, and acid halides.ClClClOThis chapter will focus on:Compounds with more than one halide can be classified by how close together the halides are. Which of these is a geminal dihalide, and which is a vicinal dihalide?Cl ClClClLG Ch 9 p 2Not all compounds that contain a benzene ring are aryl halides. Classify the following. What category do they all belong to?IClBrBrBrClOrganic halides may also contain a C=C. Classify the following. What category do they all belong to?Some aromatic halides and some unsaturated halides react like are alkyl halides, and some do not. The important factor is the hybridization of the C the halogen is attached to.sp3 carbonsp2 carbonLabel the following as methyl, 1o, 2o, 3o, allyl, and benzyl.ClClBrBrIClH ClH HBrClBrLG Ch 9 p 3Where organic halides are foundAre organic halides common in nature?Why is iodine necessary in the human diet?HOIIOIIH2N OOHWhere do we get it?What happens if you don't?How are alkyl halides used in industrial, commercial, and medical applications?H3C CClClClCClCl HHC CBrHClFFFClClClClClClClClFC ClClFCClCl HClPreparation of alkyl halidesHow can alkyl halides be synthesized from alkanes?What difficulty does this reaction have?What kind of intermediate is formed in this reaction?LG Ch 9 p 4What stabilitzes radical intermediates?What would the products of the following reaction be?excess Cl2h! or heatWhat reagent can be used in place of Br2?NBSCl2h!h!Why are the following reactions successful at forming only one major product?Cl2h!Spectroscopy of alkyl halides What IR bands does this alkyl halide spectrum have?Is IR a good way to identify alkyl halides?LG Ch 9 p 5 BrHow can you locate the H's on a C with a halogen attached?Assign the H's on the following spectrum.Reactivity of alkyl halidesGive the order of electronegativity of halogens atoms:Give the order of size of the halogen atoms:Give the order of bond strength of C-X:Show the polarity of the carbon-halogen bond:ClShow how an alkyl halide can react in each of the following ways:dissociation:Cldisplacement:Clacid/base:ClWhat do all of these reactions have in common?LG Ch 9 p 6Nomenclature of alkyl halidesWhat are the two ways to name alkyl halides?How do you construct a common name?Give the common names for the following compounds.BrFClIClClBrBrWhy can't you write a common name for the following compound?ClReview the steps for naming a compound using IUPAC rules.LG Ch 9 p 7Give names for the following compounds.ClBrIBr BrBrClII. Substitution reactions of alkyl halidesIntroductionWhat are the two types of reactions that alkyl halides can do?Which of the reactions represented below is a substitution reaction? Which is an elimination reaction? Why?ClNa+NaCl+OK+OH++KBrBrHOOWhich of these will we study in this chapter? In the next?MechanismsWhat is a mechanism?How many ways can a substitution occur? What are the mechanisms called?LG Ch 9 p 8SN2:ClNaO+NaClOWhere is the nucleophile, and where is the electrophile?What type of Lewis acid/base reaction is this?How could this mechanism be described?Why is the alkyl halide a good electrophile?Why is the alkoxide a good nucleophile?ClCl+OHOHOOHH+OHSN1:What type of reaction is this?How could this mechanism be described?Where are the nucleophile, electrophile, acid, and base?Why can alkyl halides dissociate?Why is the carbocation a good electrophile?LG Ch 9 p 9Which substitution reaction?How are the SN1 and SN2 reactions the same?Which are the two electrophiles used in the examples? Which do you think is more reactive? Why?SN1SN2What are the two nucleophiles used in the examples? Which do you think is stronger, and why?SN1SN2How do the strength of the nucleophile and electrophile fit together?Following the pattern of the reactions given previously, draw the mechanisms for the following reactions:BrSN2C NNaBrSN1HOHScenario A: strong Nu added to alkyl halideScenario B: weak Nu added to alkyl halideWhat determines whether an SN1 or and SN2 reaction will occur?LG Ch 9 p 10Nucleophiles in Substitution Reactionsalkyne anionscyanidehydroxidealkoxidesthiolateshalidestert-butoxidewateralcoholstert-butyl alcoholThe following are nucleophiles commonly used in substitution reactions, listed in order of nucleophilicity:exception:exception:What is the cut off point between nucleophiles that follow SN2 vs. SN1 mechanisms?Why is are alcohols weak nucleophiles while alkoxides are strong nucleophiles?Why won't tert-butoxide and tert-butyl alcohol work as nucleophiles?Why are alkyne anions the best nucleophiles?Which of the halides is the best nucleophile? Why are they all poor nucleophiles?LG Ch 9 p 11OBr+NaSIOHOH HBrBrBrBr++++NaNaProductsGive the products of the following reactions. Then note what nucleophile produced what product. Which mechanism will each follow?BrNa+Br+NCHONaBr+NaLG Ch 9 p 12StereochemistryWhat happens to a stereocenter involved in an SN2 reaction?ClCan a substitution reaction involve a carbon that is a stereocenter?Can a substitution reaction create a new stereocenter?NaOHHow does this happen?HClWhat happens to a stereocenter involved in an SN1 reaction?ClH2OHow does this happen?HClThe actual ratio isn't 1 to 1 - it's more like 2 to 3. Why?LG Ch 9 p 13What happens to the rate of SN2 reactions as the substitution increases?Rate lawsONaONaClDraw the energy diagram for this reaction.ClConsider the following SN2 reaction.Which reagents are involved in the rate limiting step?Write the write law:What is the order of the alkyl halide? the nucleophile?What does SN2 stand for?What would happen if youdoubled the concentration of the alkyl halide?doubled the concentration of the nucleophile?Draw the structure of the transition state.ClClClCH3Clsteric hindranceactivation energyrate of