Organic II Quizzes + Worksheet Flashcards
The mass spectrum of alcohols often fails, to exhibit detectable M+ peaks but instead show relatively large ________ peaks.
M-18
An odd molecular ion peak usually indicates what?
The presence of an odd number of nitrogen atoms in the molecule.
Which of the following fragment peaks would not be present in the mass spectrum of n-hexane?
29
43
57
71
87
87
What type of feature will be observed in the EI mass spectrum of chlorobenzene?
A signal at 112 and a signal at 114 in a ratio of 3:1
The presence of iodine have a peak of m/z at ___ on the mass spectrum.
127
For DEPT-135 what appears normally?
CH3 (methyl) and CH (methine) groups
How many different kinds of carbons in 2-methylpentane?
5
Anions for allylic species ________ (add or subtract) an electron.
add
Bonding for MOs means what?
All orbitals are bonded (+ w/ + and - w/ -)
Antibonding means what?
Max nodes or no bonded orbitals.
H2SO4 with 2 alcohols create what?
An ether (R-O-R’)
What does MCPBA do to a double bond?
Create an epoxide (triangle w/ O)
Which has a lower b.p? Ether or alcohols?
Ether.
Ether reacting with HI (excess) and heat produces what?
A cleavage of 2 iodine molecules.
What does 1. Hg(OAc)2, CH3CH2OH, 2. NaBH4 do to a cyclic compound with a double bond?
Removes the double bond and add a OCH2CH3 substituent.
What is the best path for the Williamson Ether Synthesis?
Primary alkyl halide and NaO-R compound.
Is CH3OH an acid or base?
Attacks more or less substituted carbon for an epoxide?
Acid; more substituted
(OCH3 attacks less substituted)
Is NaOCH3 a strong base or acid?
Strong base… attacks less substituted carbon
The mass spectrum of which molecule has M+ & M+2 peaks of approximately equal intensity?
Bromine
The presence of which element is indicated by a peak at m/z 127 and a characteristic 127-unit gap in the mass spectrum?
Iodine
What usually indicates the presence of an odd number of nitrogen atoms in the molecule?
An odd molecular ion peak.
The mass spectrum of which compound has an M+2 peak that has intensity that is about 25% of its M+ peak?
Chlorine
The mass spectrum of which compound has an M+2 peak that has intensity that is about 4% of its M+ peak?
Sulfur
What are the 2 modes of cleavage for alcohols?
At the alpha carbon and the allylic carbon.
A reaction under kinetic (or rate) control will yield predominantly…
the product whose formation requires the smallest free energy of activation.
Kinetic control gets a ___ product while thermodynamic control get a ___ product.
1,2- ; 1,4-
Which forms faster, kinetic or thermodynamic control?
Kinetic
What temperature is the thermodynamic and kinetic control at?
Thermodynamic: 40
Kinetic: -80
Which control is irreversible? Thermodynamic or kinetic?
Kinetic
Does the double bond move for thermodynamic control reactions?
Yes.
How many electrons are present in the nonbonding π molecular orbital of the allyl anion?
2
In an allyl cation, how many pi electrons are there?
2
A thermodynamically-controlled reaction will yield predominantly…
the more/most stable product.
Grignard reagents add to the ____ substituted carbon for epoxides.
less
Give the formula for a Grignard reagent.
CH3MgBr
Do ethers have much lower water solubilities than alcohols?
No.
What reagents is suggested for adding an methoxy group to an epoxide?
NaOCH3 and CH3OH
or
CH3MgBr, H3O+
What reagents is suggested for adding an methoxy group to a double bond?
- Hg(OAc)2, CH3OH
- NaBH4
What does CH3CO3H do to a double bond?
Change double bond to an epoxide.
MCBPA and CH2Cl2 reagent with a cyclohexene produces what?
An epoxide on the cyclic compound.
