Ethers & Epoxide; Thiol & Sulfides COPY Flashcards
Ethers
Are compounds that exhibit an oxygen atom bonded to two R groups
What are the two different methods for naming ethers?
- A common name is constructed by identifying each R group, arranging them in alphabetical order & adding “ether” at the end (ex. ethyl methyl ether)
- A systematic name is made by choosing the larger group to be the parent alkane & naming the smaller group as an alkoxy substituted (ex. ethoxypentane)
An ether can act as a ___________ & interact with the proton of an alcohol (Bu they can’t make hydrogen bonds with themselves) (Boiling point lower than alcohols)
Hydrogen bond acceptor
Ethers can have ___________ innteractions
Dipole-Dipole
Ethers can interact with ________ that have either a full positive charge or partial positive charge
Metals
The formation of a Grignard reagent is formed with an ___________
Ether
Polyethers
Compounds that have multiple ether groups & they have stronger interaction with metals
Crown ethers are an example of what?
Polyethers
____________ contain multiple oxygen atoms & are therefore capable of binding more tightly to metal ions
Crown ethers
The nomenclature for crown ether is _____________ where X indicated the total number of atoms in the ring & Y indicates the number of oxygen atoms
X-crown-Y
Without ________ the KF wouldn’t dissolve in benzene
18-crown-6
The use of _______ allows the creation of free fluoride ions in a nonpolar which makes a substitution reaction possible
18-Crown-6
Diethyl ether can be prepared ____________ by an acid- catalyzed dehydration of ethanol (SN2) reaction
Industrially
Ether can be prepared via two step process called _____________ ether synthesis
Williamson
What is the mechanism for Williamson ether synthesis?
- Proton transfer
- Nucleophilic attack
Alkoxymercuration-demercuration
Is adding an alcohol RO & H to a double bond to form an ether
Acidic cleavage
When heated with concentrated solution of a strong acid, an ether will undergo acidic cleavage in which the ether is converted into two alkyl halides
What is the mechanism for acidic cleavage of an ether?
- Proton transfer
- SN2
When phenyl ether is cleaved under acidic consition the products are ________ & _______
Phenol & an alkyl halide
Both _____& _____ are used cleave ether
HBr & HI
Ethers undergo autooxidation in the presence of atmosphere oxygen to form ______________
Hydroperoxides
Cyclic ethers
Are compounds that contain an oxygen atom in a ring
Oxiranes
Are cyclic ethers that contain a 3-membered ring system
Epoxide
Are substituted oxiranes that can have up to 4 R groups
The simplest epoxide is called what?
Ethylene oxide (common name)
What are the two ways to name epoxides?
- The oxygen atom is considered to be a substituent on the parent chain & the exact location of the epoxide group is identified with two number followed by the term’s “epoxy” (ex. 3-ethyl-2-methyl-2,3-epoxypentane)
- The parent is considered to be the oxirane ring & any group connected to the ring is a substituent (ex. 2,2-diethyl-3,3-dimethylloxirane)
Alkenes can be converted into epoxides when treated with ____________
Peroxy Acid
__________ & _____________ acid are the most common peroxy acids
MCPBA & Peroxyacetic
The process of coverting an alkene to an epoxide is __________ where if a substituent is cis in the alkene (reactant) then its cis in the epoxide (product) & same with trans
Sterospecific
Alkene can be converted into halohydrin with a halogen & water where it can then by converted into an epoxide when treated with a ___________
Strong base (like NaOH)
What is the mechanism for an epoxide formation from a halohydrin?
- Proton transfer
- Intramolecular SN2
An epoxide can be formed from an __________
Alkene (use 1. Br2, H2O 2. NaOH) or with MCPBA
To get a chiral epoxide would have to use _________ where you can use either (+)-DET or (-)-DET
Chiral catalyst (stereochemical outcome (whether its R or S depends on whether (+) or (-) DET was used)
When a epoxide is subjected to attack by a ___________ a ring-opening reaction occurs
Strong nucleophile
What is the mechanism for epoxide ring- opening with a strong nucleophile?
- Nucleophilic attack
- Proton attack
When doing a ring opening epoxide with a strong nucleophile what are the two things have to consider?
- Regio chemistry
- Stereochemistry
What is the Regio chemistry in a ring opening reaction with a strong nucleophile?
When the starting epoxide is unsymmetrical the nucleophile attack the less substituted position
What is the stereochemistry of a ring opening reaction with a strong nucleophile?
When the attack takes place at a chiral center an inversion occurs
What is the mechanism for the preparation of sulfides from thiols?
- Proton transfer
- SN2
Sulfides also undergo oxidation to produce ___________ & ___________
Sulfoxides & Sulfones (1st it produces sulfoxide & it oxidized again produces sulfone)
__________ is the oxidizing agent used to convert sulfide into sulfoxide without oxidizing it into a sulfones
NaIO4 (Sodium meta-periodate)
If sulfone is the desired product, then 2 equivalent of___________ is used to convert it into
Hydrogen peroxide
