1 Chem 2261 Checklist and Practice Questions for Chapters 8-10 Chapter 8Rank alkyl halide substrates in order of reactivity in an SN2 (or SN1) reaction. Rank nucleophiles in order of reactivity in an SN2 (or SN1) reaction. Rank leaving groups in order of reactivity in an SN2 (or SN1) reaction. Rank solvents in terms of effectiveness (reaction rate) in an SN2 (or SN1) reaction. Draw and/or explain products (including stereochemical outcome where appropriate) an SN2 (or SN1) reaction. Distinguish between substrates and/or reaction conditions likely to favor the SN2 or SN1 mechanism for nucleophilic substitution. Carbocation Stability Carbocation Rearrangement.Chapter 9Draw and/or explain products (including selectivity where appropriate) an E2 (or E1) reaction. Types of Selectivity Regioselectivity Reactions which follow Zaitsev's Rule (i.e., give the more stable alkene product). Exceptions to Zaitsev's Rule (for example: alkyl fluorides). Stereoselectivity Consequences of requirement for C-H and C-X to be antiperiplanar in E2 reactions. Distinguish between substrates and/or reaction conditions likely to favor substitution (SN2 or SN1) or elimination (E2 or E1). Chapter 10Nomenclature of alcohols Conversion of alcohols to alkyl halides By reaction with HX By reaction with PBr3, PCl3, or SOCl2. Conversion of alcohols to alkyl tosylates (ROH to ROTs). Controlling stereochemistry for nucleophilic substitution reactions involving secondary alcohols. Conversion of an alcohol to a halide (using PBr3, PCl3, or SOCl2) occurs with inversionof configuration (because oxygen of alcohol gets displaced in SN2 reaction). Conversion of an alcohol to a sulfonate ester occurs with retentionof configuration (because carbon-oxygen bond of alcohol retained; no SN2 displacement) Dehydration (conversion of alcohols to alkenes) 3° alcohols are more reactive (room temp. reaction) and 1° and 2° alcohols (which require heating) 2° and 3° alcohols undergo SN1 (⇒look for carbocation rearrangement) 1° undergo SN2 (⇒no carbocation rearrangement possible) Formation of Ethers Williamson Ether Synthesis (SN2 reaction of an alkoxide) Identify preferred alkyl halide/alkoxide combination for synthesis of an unsymmetrical ether. Via carbocation intermediates Formation of epoxides from halohydrins Nucleophilic substitution reactions of epoxides Ring-Opening under Basic Conditions Regiochemistry = Nucleophile adds to less substituted sideRing-Opening under Acidic Conditions Regiochemistry = Nucleophile adds to more substituted sideStereochemistry = inversion of configurationfor either type of epoxide ring-opening.
has intentionally blurred sections.
Sign up to view the full version.