Chapter 8 Flashcards
What happens during an Alkene Addition of H-X? Do we need to know the mechanism?
Hydrogen attaches to the least substituted C of the double bond, producing a carbocation. After a potential carbocation rearrangement, the halogen attaches to the carbocation
X attaches the the most substituted side, with possible carbocation rearrangement
What are the substrates in an Oxymercuration/Demurcuration reaction?
Hg(OAc)2/THF/H20
NaBH4/OH-
What happens in a oxymercuration/demercuration reaction? Do we need to know the mechanism?
Use Hg(OAc)2/THF/H20, then NaBH4/OH-
OH goes to the most substituted side, the H goes to the least substituted side (always)
What are the substrates for an Acid Catalyzed Hydrogenation?
Acid(ex: H+, dilute)/H2O
What happens in an Acid Catalyzed Hydrogenation? Do we need to know the mechanism?
The OH goes to the most substituted side, the H goes the least substituted side. There is a possible carbocation rearrangement, so we need to know the mechanism.
What are the substrates for a Hydroboration/Oxidation Reaction?
BH3/THF
H2O2/NaOH
What happens in a Hydroboration/Oxidation Reaction? Do we need to know the mechanism?
Use BH3/THF then H2O2/NaOH
The OH goes to the least substituted side, the H goes to the most substituted side (always)
What happens in an Addition reaction of Dihalogens (X2) in Organic Solvents? Do we need to know the mechanism?
The Halogen(X) is added to each carbon of the double bond (diagonal from each other) We do not need to know the mechanism.
What happens in an Addition reaction of Dihalogens(X2) in Water? Do we need to know the mechanism?
A Halogen(X) is added to the least substituted side, the OH goes to the most substituted side
What happens in an Oxidation reaction of Alkenes with COLD/DILUTE Permanganate in basic solution? Do we need to know the mechanism?
An OH is added to each carbon of the double bond syn. (forming Cis-1,2-diols) We do not need to know the mechanism.
What happens in an Oxidation reaction of Alkenes with Osmium Tetroxide (OsO4)? Do we need to know the mechanism?
An OH is added to each carbon of the double bond syn. (forming Cis-1,2-diols) We do not need to know the mechanism.
What happens in an Oxidative Cleavage reaction of Alkenes with HOT, basic Permanganate, then H+? Do we need to know the mechanism?
Depending on the alkene, different products will form. A double bond O will replace the double bond on each side, and an OH will replace each H bonded to the carbons.
H2C= -> (OH)2C=O (Carbonic Acid) -> CO2 +H2O
RHC-> (OH)(R)C=O (Carboxylic Acid)
R2C -> R2C=O (Ketone)
We do not need to know the mechanism
What happens in a Cleavage of Alkenes via Ozonolysis (O3) reaction (Me2S is also added)? Do we need to know the mechanism?
Depending on the alkene, different products will form. The double bond will be cleaved by oxygen; oxygen will attach to the double bond on both sides. This will form either aldehydes (at least one H) or ketones.
We do not need to know the mechanism.
What happens in an Addition Reaction to Alkynes? Do we need to know the mechanism?
Each time you add HX, the H will go to the less substituted side and the X will attach to the more substituted side. If you do the reaction twice, the two halogens will attach to the same side/carbon (forming a geminal dihalide). We do not need to know the mechanism.
What happens in an Addition reaction of Dihalogens(X2) to Alkynes in Organic solvents? Do we need to know the mechanism?
The Halogens will attach on opposite sides (diagonal), first forming an alkene with a halogen on each side, then an alkane with two halogens on each side. We do not need to know the mechanism.
What are the possible substrates in a Hydrogenation of Alkyne reaction? What products will they produce?
NiB2(P-2) or Pd/CaCO3 produces Cis-Alkenes,
Li/NH3 or Na/NH3 produces Trans-Alkenes,
Pd/Ni/Pt/Rh/Ru produces an Alkane
Alkene + HX -> ?
Carbocation rearrangement? Stereochemistry? Syn, anti, or N/A?
Alkyl Halide, halogen on most substituted side of double bond.
Possible carbocation rearrangement. Produces Enantiomers because trigonal planar. (racemic mixture).
Alkene + H+/H2O -> ?
Carbocation rearrangement? Stereochemistry? Syn, anti, or N/A?
Alcohol, OH on the most substituted side of double bond.
Possible carbocation rearrangement. Produces Enantiomers because trigonal planar. (racemic mixture)
Alkene + Hg(OAc)2/THF/H2O + NaBH4/OH- -> ?
Carbocation rearrangement? Stereochemistry? Syn, anti, or N/A?
Alcohol, OH goes to the most substituted side of double bond. No possible carbocation rearrangement or enantiomers. Anti addition.