Chem 14D Spring 2010 Garg Midterm 1 Review Practice Problems Some Topics to Study very broad Reactivity stuff Classify atoms as electrophilic or nucleophilic Definitions of nucleophiles electrophiles Nucleophiles Leaving groups Solvent types pKa of common acids Steric hindrance Arrow pushing SN2 Mechanism Stereochemistry Transition state Reaction coordinate diagram Inter and intramolecular examples Solvent trends solvation SN1 Mechanism solvolysis Stereochemistry Transition state Reaction coordinate diagram Solvent trends E1 and E2 Mechanisms Stereochemistry Solvent reaction condition trends Alcohol Synthesis Nucleophilic additions to carbonyls NaH vs NaBH4 LiAlH4 Organolithium reagents Grignard reagents Oxidation chromium reagents Retrosynthetic analysis PRACTICE QUESTIONS NKG 4 19 10 1 Consider the following solvents For each draw the structure and circle the appropriate solvent classification a isopropanol Structure d Acetone Classification Circle one answer polar protic polar aprotic polar aprotic nonpolar aprotic nonpolar aprotic e THF Classification Circle one answer Structure Classification Circle one answer polar protic polar protic polar aprotic polar aprotic nonpolar aprotic nonpolar aprotic f water c HMPA Structure Classification Circle one answer polar protic b DMF Structure Structure Classification Circle one answer Structure Classification Circle one answer polar protic polar protic polar aprotic polar aprotic nonpolar aprotic nonpolar aprotic NKG 4 19 10 2 For each compound shown below indicate whether the compound is nucleophilic or electrophilic at the marked atom a c e O OTs Me O S O N d b H2O N 3 Consider the following elimination reactions For each a draw the major product b determine if the elimination proceeds by E2 or E1 circle your answer Br NaOEt EtOH OTs E1 or E2 MeOH heat E1 or E2 OH cat H2SO4 benzene heat Br E1 or E2 t BuO K t BuOH E1 or E2 NKG 4 19 10 4 Consider the following substitution reactions For each a draw the major product s that arise from substitution b determine if the given substitution takes place by SN2 or SN1 circle your answer EtONa Br SN1 or SN2 DMSO NaI Cl acetone SN1 or SN2 I H2O SN1 or SN2 Br MeOH SN1 or SN2 5 a Which of the following two substrates would likely undergo faster E2 elimination circle your answer H H Br Br or H A H B b Provide an explanation for your answer that includes 3 dimensional drawings NKG 4 19 10 6 Rank the following in order of nucleophilicity 1 being most nucleophilic 4 being the least nucleophilic CH3MgBr EtO EtOH t BuOH 7 Based on your knowledge of pKa values rank the following in order of leaving group ability 1 being the best leaving group 4 being the worst leaving group Br TsO CN CH 3 8 Draw a reaction coordinate diagram for the following reaction Be sure to label starting material s transition state s product s activation energy ies and intermediate s if applicable Cl N3 NaN3 acetone 9 Provide reaction conditions for the following transformation place your answers above and below the reaction arrows NKG 4 19 10 OH O Br 10 Provide a synthetic scheme for the following conversion Cl N3 11 Amanda has performed a retrosynthetic analysis on Compound F After performing several disconnections she arrived at bromobenzene and acetaldehyde shown below Provide a forward synthesis of Compound F that relies on Amanda s strategy OH Me Me Br O H Me F NKG 4 19 10 12 Grace has performed a retrosynthetic analysis on Compound A After performing several disconnections she arrived at allyl bromide and carbon dioxide shown below Provide a forward synthesis of Compound A that relies on Grace s strategy O Br O CO2 A 13 Draw an arrow pushing mechanism for the following transformation O NaBH4 OH EtOH 14 Draw an arrow pushing mechanism for the following solvolysis experiment I OEt EtOH 15 Draw an arrow pushing mechanism for the following elimination reaction Br MeOH heat NKG 4 19 10 This is the instruction page for Exam 1 Chem 14D Exam 1 Spring 2010 Prof Neil Garg Friday April 23 2010 1 00 1 50 PM General Instructions This is a standard closed note exam Please read each question carefully and write your answer neatly in the space provided using a black or blue pen no pencils You may use the back of the pages and page 6 as scrap paper The use of model sets is allowed A periodic table is provided on the last page of the exam Cell phones calculators headphones are not permitted Keep your Student ID card out for ID Check GOOD LUCK NKG 4 19 10