CHEM 210 REACTIONS EXAM NEWEST QUESTIONS AND ANSWERS (2023 / 2024) (VERIFIED ANSWERS)

What is the degree of substitution? ANSWERSThe number of alkyl groups a specific carbon is bonded to (more alkyl groups means more stable) What reagents are required in a dissolving metal reduction? ANSWERSNa or Li, ammonia (NH3) as solvent Provide a summary of dissolving metal reduction ANSWERS2 hydrogens (one equivalent) are added to an alkyne to form the E alkene (anti addition) What is the stereochemistry of the dissolving metal product? ANSWERSE alkene (anti addition) What reagents are used for a hydrogenation with a poisoned catalyst? ANSWERS- H2 - Metal (usually Pd) - Solid Support (BaSO4 or CaCO3) - Additive (PbO or quinoline) FACT CHECK THIS IN BOOK What is the stereochem for hydrogenation with poisoned catalyst? ANSWERSSyn addition; forms Z alkene Provide a summary for what happens in a hydrogenation of an alkyne ANSWERSH2 will continue to be added until the molecule is fully saturated (one equivalent is added at a time, syn addition) What are the reagents for catalyzed hydrogenation? ANSWERSH2 and a catalyst (like Pd/C) Provide a summary for what happens in an epoxidation ANSWERSOxygen is added to an alkene to form an epoxide What reagents are necessary for an epoxidation? ANSWERSPeroxy acid and an alkene What is the stereochem for an epoxidation? ANSWERSSyn addition (top or bottom) What is the regioselectivity for an epoxidation? ANSWERSNone Describe the mechanism for an epoxidation ANSWERSThe oxygen that becomes the epoxide is the one in the alcohol, double bond captures hydrogen, remaining bond closes the circle, forms other double bond Provide a summary for what happens in a halogenation ANSWERSAlkene adds a halogen group and nucleophile group (through a halonium ion intermediate) What reagents are required for a halogenation? ANSWERSHalogen source (diatomic halogens, mixed halogen diatomics, NBS, NCS) and nucleophile (monoatomic halogen anions, H20, NaOH, CH3OH, NaOCH3) What is the stereochem for halogenations? ANSWERSOverall anti addition (the first step is syn addition to form the halonium ion, and the second step adds the nucleophile from the opposite side, like in Sn2) Describe the mechanism for a halogenation ANSWERSStep 1) Form halonium ion Step 2) add nucleophile (analagous to Sn2) What is the regioselectivity for halogenations? ANSWERSThe nucleophile follows the Markovnikov rules (adds to the more stable carbon - resonance degree of substitution) If you have a mixed halogen diatomic as your reagent for a halogenation, how do you know which halogen to use in the first step, and which to use as the nucleophile? ANSWERSThe halogen used in the first step should be whichever will make a more stable halonium ion intermediate (this should be the less eN halogen), and the other will therefore be used as nucleophile Provide a summary for the ozonolysis of an alkene using an oxidative workup ANSWERSAlkene breaks apart and is replaced by a double bond to oxygen; if the alkene had a hydrogen substituent, this will become an OH group Provide a summary for the ozonolysis of an alkene using a reductive workup ANSWERSAlkene breaks apart and is replaced by a double bond to oxygen (no substituents are changed) What are the reagents for ozonolysis? ANSWERSOzone (O3) and either an oxidative agent (like H2O2) or reductive agent (Zn) Identify the equivalence point on the titration curve. Define the end point of