Test 1 Flashcards
What is the mechanism for adding a metal hydride (XH) to an alcohol
H attacks H which goes to O. O ends up attached to X creating an H2 byproduct
What is the mechanism for adding elemental X to an alcohol
X releases an electron which attacks H going to O. O is attached to X creating an H2 byproduct
What is the mechanism for adding HX to a primary alcohol and what type of rxn is it
H attacks O, X attacks postive O creating H2O byproduct and Cl taking the place of OH. Inversion may happen Sn2
What is the mechanism for adding HX to a secondary alcohol and what type of rxn is it
CH3-CH(OH)-CH-(CH3)2
H attacks O, carbocation is created, rearrangement if needed, X attacks postive charge. May create a racemic mixture and an enantiomer Sn1
What is the mechanism for adding HX to a tertiary alcohol and what type of rxn is it
(CH3)3-C-OH
H attacks O, carbocation is made, X attacks postive charge. May create a racemic mixture Sn1
What is the mechanism for reactions with PBR3 and Pry and what type of rxn is it
CH3-CH(OH)-CH2-CH3
O attacks PBR3 onto Br, adding PBR2 to O, Pry attacked H which attacks O, BR attacks C that O is on, creates an inversion and byproduct of OPBr2. Sn2
What is the result of a rxn with SOCl2 to an alcohol and what type of rxn is it
CH3-CH2(OH)-CH2-CH3
Cl is added where OH is in the opposite conformation. Sn2 makes an inversion
What is the structure of PBR3
3 BRs attached to P individually and a lp on P
What is the structure of Pryidine (Pyr)
ring with 3 double bonds and a N in place of a C
What is used for a dehydration rxn
heat and a strong acid catalyst
What is the mechanism for adding H2SO4 to a secondary alcohol and what type of rxn is it
O on OH attacks H onto O os H2SO4, Protonation by bond going to O, O of H2O attacks H of adjacent bond onto bond making a double bond. E1
What is the mechanism for adding H2SO4 to a primary alcohol and what type of rxn is it
CH3-CH2-CH2-CH2-OH
OH attacks H onto O, rearrangement if needed, H2O attacks H onto bond, to make a double bond, produces a major and minor product. E1
What happens to the three types of alchols in an oxidation rxn
primarys become aldehydes onto carboxylic acid if water is present, secondary become ketones and tertiary has NR
What is the mechanism for adding DMP to an alcohol
CH3-CH(OH)-CH3
O attacks I of DMP which goes on to one OAc causing DMP (minus one AOc) to attach to O of alcohol, free OAc attacks H of postive O which moves to O, triethylamine attacks H of OAc which eventually goes to an OAc of I resulting in a ketone and DMP with one OAc
What is DMP
Cyclohexane ring attached to a cyclopentane ring that has an I in 1 attached it 3 OAcs, an O in 2 and a O double bonded to 3
What is OAc
O-C(=O)-CH3
What does adding PCC and CH2Cl2 to an alcohol cause
O is double bonded to the C before OH. Will not oxidize primary alcohols to an carboxylic acid
What does adding (COCl)2, DMSO, CHCl2, and Et3N in -78 celcius do to an alcohol
Adds double bond O to C before OH and makes OH H, creating byproduct of DMS
What is DMSO
(CH3)2- S=O
What is (COCl)2
Cl-C-C-Cl
II II
O O
What does adding HIO4 to an a diol do
Causes OH to split apart while becoming =O, only happens to vicinal diols (OH on adjacent Cs)
What are the reagents for a Jones Oxidation
CrO3, H2SO4, and heat
What is the result of a Jones Oxidation
O is double bonded to the C before OH. Will not oxidize primary alcohols to an carboxylic acid
What happens as a result of adding TsCl or MsCl to an alcohol
An Sn2 rxn will take place if a nucleophile is used resulting in the nucleophile taking place of the OH and Ts/MsO- being a byproduct. An E2 rxn can take place if a base is used resulting in an alkene
What is the PKa range for alcohols
16-18
How do you find the common name of ethers
Name R and R’ as substituents, list them alphabetically, and add ether at the end
How do you find the IUPAC name of ethers
Name the smaller OR group as an alkyl and replace the -yl as -oxy and put first then name the other group as normal
What is the mechanism for an acid catalyzed dehydration and what type of rxn is it
2CH3-CH2-OH
OH attacks H+, the OH of the second ether attacks the C next to water causing protonation, conjugate base attacks H of new ether which goes to O making CH3-CH2-O-CH2-CH3 and water. Sn2
What is the mechanism for a Williamson ether synthesis and what is the rxn
CH3-CH2-O-Na+ + Ch3-CH2-Br
The O- attacks the C next to the halide which then goes to the halide making CH3-CH2-O-CH2-CH3. Sn2
What are the rules for preparing ethers for a williamson ether synthesis
Place the halide on a primary substrate or methyl if possible. If the halide is on a secondary substrate then an Sn2 rxn competes with an E2 to make an ether and alkene mix. If the halide is on a tertiary then only E2 takes place then no ether form
Prepare the following ether for an Williamson ether synthesis
pentane ring -O-CH3
The less substituted carbon (CH3) bond will be broken via a reverse Sn2 rxn making a pentane ring connected to O-Na+ and CH3-Br
What is the mechanism for an acid catalyzed addition of alkenes to alcohols/ethers
CH3-C=CH2
Pi bond attacks the H+, O of CH3-OH attacks positive C, lone pair of CB or CH3-OH attacks new H to O creating CH3-CH (OCH3)-CH3
What is the mechanism for adding 1 eq of HI to a symmetrical ether
CH3-CH2-O-CH2-CH3
O attacks H then I attacks C next to O onto O making an alkyl halide (CH3-CH2-I) and an alcohol (CH2-CH2-OH)
What is the mechanism for adding 1 eq of HI to an unsymmetrical ether and what is rxn
CH3-O-CH2-CH3
O attacks H of HI, I attacks the less hindered C onto O. Sn2
What are the rules of adding 1 eq of HI to an unsymmetrical ether
If both Cs on the side of O are primary then the rxn is Sn2 but if either is not primary then the rxn will be Sn1
What is the mechanism for adding excess halide to an unsymmetrical ether
CH3-CH2-CH2-CH2-O-CH2-CH3
O attacks H onto Br, Br attacks least hindered C onto O, breaking the molecule in half adding OH to one and Br on the other. The excess Br adds Br in the place of OH
What is the result of adding excess halides to a symmetrical ether. What is the rxn
CH3CH2-O-CH2CH3
2 CH3-CH2-Br and H2O, Sn2
What is the special case of adding halides to ethers
A halide can’t be added to an sp2 carbon meaning that the rxn wouln’t proceed
How do you name an epoxide
Add “oxide” to the end of an alkene name
What is mCPBA
Benzene ring with Cl attached to the bottom, C attached to the right (=O)-O-OH
What is the mechanism for peracids with alkenes
C(CH3)=C(CH3)
double bond attacks O onto bond between O and C, double bond between C and O attacks H of itself onto lower C. Makes Syn epoxide and carboxide. But if the starting molecule were not symmetrical then an enantiomer will be made
What is the mechanism for an epoxide synthesis via halohydrins
CH2(OH)-CH2-Cl
H of strong base attacks H onto O, O attacks C next to halide onto halide making an epoxide abd NaCl
What is the mechanism for and H+ catalyzed epoxide ring-opening and what is the rxn
heptane ring with two wedges connected to same O
O attacks H+, O of H2O attacks either C onto O, lp of CB attacks H onto O creating a heptane ring with OH added anti and an enantiomer. Sn2
What is the mechanism for an OH- catalyzed epoxide ring-opening
heptane ring with two wedges connected to same O
OH attacks carbon onto O, O connected to Na attacks H onto O creating heptane ring with OH added anti conformation
What is the mechanism for ring opening with a nucleophile other than OH and H2
Epoxide C(CH3)2-O-CH2- same C + H+ and CH3-OH
O attacks H+, OH attacks (neutral Nuc) more substituted side onto O, lp of conjugate base attacks H onto O
When placing an arrow to describe the relationship between reactants and products what are the criteria?
If there is only an excange of electrons then there is a resonance relationship, if atoms do move then the more favored one is the more stable one
