Ch. 10 Flashcards
(25 cards)
When naming an alkene what is important to remember?
The longest chain must contain both atoms of the double bond
How do you the suffix if there is more than one double bond in the molecule?
Change the -ane ending to -adiene (for two double bonds), -atriene (for three), and so forth
Where is the double bond located in a cycloalkene?
Between C1 and C2
What class of compounds contain both a double bond and a hydroxy group?
Alkenols
Does the double bond or the OH group get priority when naming an alkenol?
The OH group gets the lower number when naming the longest chain
True/False: When naming a cycloalkene molecule the numbering is done clockwise or counterclockwise such that the lower number goes to the first substituent after the double bond has been numbered
True
When are the E and Z prefixes useful in naming?
When there are more than two alkyl groups bonded to the C=C
What is an allyl group?
When a substituent is bonded to a carbon adjacent to (but not part of) the double bond
What is a vinyl group?
When a substituent is bonded directly to a carbon of the double bond
Do alkenes have low or high boiling points and melting points?
Low melting and boiling points due to weak van Der Waals forces
Are alkenes soluble in water or organic solvents?
Organic solvents
As double bonds increase what happens to the melting point of fatty acids?
It decreases
What type of addition (syn or anti) occurs in hydroboration-oxidation reactions?
Syn addition
What type of addition (syn or anti) occurs in halogenation and halohydrin reactions?
Anti addition
What type of addition (syn or anti) occurs in hydrohalogenation and hydration reactions?
Syn and Anti addition
What types of bases are typically used to dehydrohalogenate an alkyl halide to make an alkene?
Strong bases for the E2 mechanism such as:
t-butoxide, DBU, DBN
What types of reagents are used in the acid-catalyzed dehydration of an alcohol to make an alkene?
H2SO4 and TsOH, occurring via an E1 mechanism with 2’ and 3’ alcohols, and via E2 with 1’ alcohols
What reagents are often used to carry out dehydration of a 2’ alcohol via an E2 mechanism?
POCl3 and pyridine
What reagent class is used to make an alkyl halide from a 1’ alcohol?
- -HX via an Sn2 mechanism.
- -The oxygen gets protonated to make it a good leaving group
- -The X- then does a backside attack
What reagent class is used to make an alkyl halide from a 2’ or 3’ alcohol?
HX via an Sn1 mechanism
When would you use SOCl2 + Pyridine
When you start with an alcohol and need to do an Sn2 reaction and end up with Chlorine as the new substituent on the alkyl halide
When would you use PBr3
When you start with an alcohol and need to do an Sn2 reaction and end up with Bromine as the new substituent on the alkyl halide
When would you use POCl3 + Pyridine as reagents?
When you start with an alcohol and need to do an E2 reaction and end up with an alkene
When would you use Tosylate + Pyridine as reagents?
When you want the flexibility to do an Sn2 or E2 mechanism and retain the stereochemistry when making the OH a good leaving group
