The double bond of an alkene is given an alkylborane by BH3.
Alkenes peroxide oxidizes the alkylborane to alcohol.
Adding water across the double bond converts alkenes to alcohols.
Borane is an electron deficient compound.
The BH3 can't have an octet because it has only six valence electrons.
Bridging hydrogens is one of the bonding structures found in boron compounds.
BH3 is capable of adding to a double bond.
The carbon at the other end of the double bond gets a partial positive charge when electrons are withdrawn from the pi bond.
The more carbon atom has a more stable partial charge.
The product shows the less substituted end of the double bond and the more substituted end of the hydrogen bond.
The less hindered end of the double bond is favored by steric hindrance.
The double bond is added by Borane in a single step.
Boron and hydrogen add to the less hindered carbon.
The orientation of the product is unaffected by the oxidation because the antiMarkovnikov orientation was established in the first step.
The hydration of an alkene by hydroboration-oxidation is an example of a reaction that does not follow the original statement of Markovnikov's rule, but still follows our understanding of the reasoning behind it.
Show how you would convert it.
To form 2-methylcyclopentanol, use hydroboration-oxidation.
The use of (1) and (2) above and below the reaction arrow indicates individual steps in a two-step sequence.
The pure trans isomer is the result of this synthesis.
Section 8-7C talks about this stereochemical result.
Dehydration of 1-methylcyclopentanol results in the substitution of 1-Methylcyclopentene.
The correct alkene is given byDehydration of the alcohol.
3 moles of an alkene can react with each mole of BH3.
The double bond of an alkene can be added with the H bond.
The oxidizers of trialkylboranes react exactly as we have discussed.
The preference for boron to add to the less hindered carbon atom of the double bond is reinforced by trialkylboranes.
The 1:1 monoalkylboranes are often used to simplify their structure and emphasize the organic part of the molecule.
A trialkylborane is formed when hydrogen and boron add to the same face of the double bond.
The trialkylborane has a hydroxy group in the same stereochemical position.
A racemic mixture is formed from achiral reagents.
Retention of configuration is the second step in theoxidation of the borane to the alcohol.
The alkyl group migrates from boron to oxygen when hydroperoxide ion adds to the borane.
Retention of configuration allows the alkyl group to migrate because it doesn't change the structure of the carbon atom.
The alcohol comes from hydrolysis of the borate ester.
A norbornene molecule is subjected to oxidation.
The structures of the intermediates and products should be given.
The syn addition of BH3 across the double bond of norbornene takes place mostly from the more accessible outside face of the double bond.
A product with both the hydrogen atom and the hydroxy group in exo positions can beOxidation gives a product with both the hydrogen atom and the hydroxy group in exo positions.
The reagents are achiral and the products are not.
The vicinal dihalides are formed by alkenes.
In this example, one bromine atom is attacked by the nucleophile and the other is left as bromide ion.
The bromine molecule is attacked by the pi electrons of an alkene.
The structure of the bromonium ion is similar to the structure of the mercurinium ion.
Unlike a normal carbocation, the halonium ion has filled octets.
The ring has considerable ring strain and a positive double bond due to the addition of bromine.
When bromine is added to an atom, it makes it stronger.