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208 Chapter 6
Copyright © 2017 Pearson Education, Inc.
ketone
a compound with a carbonyl group that is bonded to two alkyl groups.
O
C
R
R
Markovnikov’s rule
the actual rule is as follows: “when a hydrogen halide adds to an asymmetrical
alkene, the addition occurs such that the halogen attaches itself to the carbon
atom of the alkene bearing the least number of hydrogen atoms.” Chemists use
the rule as follows: the hydrogen adds to the
sp
2
carbon that is bonded to the most
hydrogens.
Here is a more general rule: the electrophile adds to the
sp
2
carbon that is bonded
to the most hydrogens.
mechanism of the reaction
a description of the step-by-step process by which reactants are changed into
products.
1,2-methyl shift
the movement of a methyl group with its bonding electrons from one carbon to an
adjacent carbon.
oxidation reaction
a reaction that decreases the number of C
¬
H bonds in the reactant or increases
the number of C
¬
O, C
¬
N, or C
¬
X bonds (X denotes a halogen).
oxidative cleavage
an oxidation reaction that cleaves the reactant into two or more compounds.
ozonolysis
the reaction of an alkene with ozone.
primary carbocation
a carbocation with a positive charge on a primary carbon.
reduction reaction
a reaction that increases the number of C
¬
H bonds in the reactant or decreases
the number of C
¬
O, C
¬
N, or C
¬
X bonds (X denotes a halogen).
regioselective reaction
a reaction that leads to the preferential formation of one constitutional isomer over
another.
secondary carbocation
a carbocation with a positive charge on a secondary carbon.
stereocenter
an atom at which the interchange of two groups produces a stereoisomer.
(stereogenic center)
stereochemistry
the field of chemistry that deals with the structure of molecules in three dimensions.
stereoisomers
isomers that differ in the way the atoms are arranged in space.
stereoselective reaction
a reaction that leads to the preferential formation of one stereoisomer over another.
stereospecific reaction
a reaction in which the reactant can exist as stereoisomers and each stereoisomeric
reactant leads to a different stereoisomeric product or products.