Organic Chemistry ACS Final Exam – Flashcards
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constitutional isomers
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same formula, different connectivity
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stereoisomers
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same formula, different spatial arrangement
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enantiomers
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non-superimposable mirror images
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diastereomers
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stereoisomers that are not mirror images of each other
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R configuration
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clockwise
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S configuration
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counter clockwise
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what functional groups does a peptide bond contain
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amide
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what functional groups does a lipid contain
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esters
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what functional groups do amino acids contain?
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aromatic rings
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meso compound
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molecule with multiple stereo centers and it is superimposable on its mirror image
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NO2 prefix
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nitro
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CH=CH2 prefix
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vinyl
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CH2CH=CH2 prefix
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allyl
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three types of disubstituted benzenes
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ortho-1,2 meta-1,3 para-1,4 only use when you have ONLY 2 substituents
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as you increase heat of combustion, what happens stability?
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it decreases
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Carbon 13 NMR Resonances
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0-80 sp3c 125-150 aromatic 160-180 esters/acids 200-220 aldehydes/ketones
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H 1 NMR Resonances
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0.9-1.5 sp3 C 2-2.5 allylic H 3-4.5 O-CH3 4.5-6.5 vinylic 7-8.5 aromatic 10 aldehyde 10-12 carboxylic acid
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IR Resonances
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3400 OH and NH 3100-3000 sp2 C 2100 triple bonds 1700 ketones 1600 C=C, aromatic C-C 1500 aromatic C-C
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what is the difference between phenyl and benzyl?
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benzyl has CH2 in between the ring and the substituted chain
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bond angle for sp2 hybridized?
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109.5
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what are 2 key things to lewis structures?
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1. filled octets 2. electronegative atom has negative charge
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if a ring has a charge, then it is ____
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aromatic
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a strong acid corresponds to?
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a weak base
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what does a double bond right next to acidic H mean?
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it is more acidic
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low pKa value means it is...
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more acidic
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how does hybridization relate to acidity?
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the more S character it is, the more acidic sp>sp2>sp3
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a hydrogen next to an electronegative atom will always be...
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more acidic
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how do you determine if molecules are meso isomers?
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needs to be chiral and needs to have a plane of symmetry
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how do you find most stable newman projection?
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it will have less gauche interactions
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what are wedges and dashes in fischer projections?
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horizontal-wedge vertical-dash
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if only one stereo center is flipped in a molecule, they are...
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diastereomers
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do racemic mixtures get plane polarized light?
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no, they cancel each other out
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do meso compounds get plane polarized light?
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no, they cannot bend light
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what can triple bonds not do stereoisomerically?
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exhibit cis or trans
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what can an enantiomer not have?
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a plane of symmetry
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what happens with a dehydrohalogenation reaction?
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H wants to attack and form a double bond to increase stability
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a strong acid corresponds to a ________ nucleophile
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weak
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how do you tell if it is a syn or anti addition?
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Syn- two atoms are either both forward/back Anti-one atom forward and one back
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where does hydroboration put the substituent?
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on the less substituted side (anti-markovnikov)
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what are the most stable types of free radicals?
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allylic or benzylic tertiary>secondary>primary
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what are the 3 steps of a free radical reaction?
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initiation-goes from 0-1 radicals propagation- goes from 1 to another 1 termination-goes from 2-0 radicals
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what is the energy of propagations like?
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very low activation energy
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what does non-regioselective mean in terms of energy?
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it goes down in energy
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what does it mean if an alcohol absorbance peak on the IR spectrum is abnormally wide?
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it is a carboxylic acid
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what does chromic acid do?
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it turns C-H bonds into C-O bonds if a molecule does not have C-H bonds, it will be unreactive with chromic acid
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E2 reactions favor ______ alkyl halides
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tertiary
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what is the trick for predicting major products of E2 reactions?
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if the base is sterically hindered, then the major product will be the LESS substituted alkene if the base is NOT sterically hindered, then the major product is the more substituted alkene
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what is the reagent BH3 * THF used for?
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hydroboration-oxidation
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how could you tell if a pair were resonance structures?
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atoms cannot be moved, only pi bonds and lone pairs
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which is more acidic: OH or NH?
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OH
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which hybridization is the most acidic?
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sp>sp2>sp3
