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Organic 2250 p i)
Exam 1, October 2, 2015 91“ l
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Fall 2009 Dr. Douglas Stack DSC 351 MWF, DSC 116, 11:00 to 11:50 am 10:00 am-11:30 pm Tuesday, 9:30- 11:00 Thursday, and/or by appointment PHONE: 554-3647, email: [email protected] TEXT: Organic Chemistry, Schmid (required) Study Guide for Schm
DIRECTION AND MAGNITUDE OF OPTICAL
Dependent on the chiral compound, i.e. some
compounds rotate (+) others (-) . Only
experimental measurement can provided the
direction of rotation.
If one enantiomer gives (+), the other enantiomer
will give (-)
The equilibrium favors the side with the weaker
acid and weaker base
Strong acids have weak conjugate bases
Weak acids have strong conjugate bases
Strong bases have weak conjugate acids
Weak bases have strong conjugate acids
ORGANIZATION OF ORGANIC REACTIONS
1. ACID - BASE REACTIONS
The transfer of a proton from an acid to a base
An atom or group of atoms is replacerd by another species
REDUCTION AND OXIDATION
REDUCTION: a net increase in bonding to hydrogen
and/or decrease in the bonding to oxygen (or other
increased bonding to hydrogen
OXIDATION: a net increase in bonding to oxygen (or
BOND LENGTH FOR CARBON-CARBON AND CARBON-HYRDOGEN BONDS
BOND C-C C-H C-C C=C C-H C-C CC C-H NOTATION Csp3-Csp3, Csp3-H1s, Csp3-Csp2, Csp2-Csp2, Csp2-H1s, Csp3-Csp, Csp-Csp, Csp-H1s, LENGTH () 1.53 1.10 1.50 1.34 1.08 1.46 1.21 1.06
BOND LENGTH FOR OTHER S
CONFORMATIONS are different spatial
arrangements of a molecule that are generated by
rotation about single bonds.
CONFORMERS are stereoisomers; their
connectivities are the same.
Conformers usually cannot be isolated since
rotation about sin
SKELETAL ISOMERS: isomers that differ in the
arrangement of the carbon chain
POSITIONAL ISOMERS: isomers that differ in
the location of a non-carbon group or a multiple
FUNCTIONAL ISOMERS: isomers with structural
differences that place then in diff
ISOMERS: compounds with identical molecular
formulas but differ in the way in which atoms are
bonded to each other
I. STRUCTURAL ISOMERS (Constitutional isomers):
Differ in the order and the way in which atoms are bonded together
A. Skeletal isomers
POSSIBLE MECHANISMS FOR
1. Bond breaking comes first, then bond-forming.
2. Bond forming comes first, then bond-breaking.
3. Bond forming and bond-breaking occur simultaneously.
1. Each of the 4 groups around the stereocenter is assigned a priority.
2. The molecule is viewed with the lowest priority group pointed away from the viewer.
3. If tracing a path from priorities 1 to 2 to 3 goes clockwise then R;
Types of Stereoisomers
Stereoisomers: Molecules with the same connectivities but
different arrangement of atoms in 3-D space.
I. Non-configurational: Conformers
i. Enantiomers with asymmetric carbons
ii. Enantiomers with
1) Work back wards from the final product;
2) Identify what functional groups are present and
identify what functional groups are precursors to
those functional groups.
3) Recognize if C-C bond forming steps are
Strong Acids and Bases in Solvents
The strongest acid that can exist, to any measurable extent,
in a solvent is the conjugate acid of that solvent. Likewise,
the strongest base that can exist, to any measurable extent,
in a solvent is the conjugate
TYPES OF CONFORMATIONAL STRAIN
Stretching Strain: The energy of stretching or
compressing a bond from its ideal length
Angle Strain: The energy of distorting a bond angle from
its ideal angle
Torsional Strain: Strain due to non-staggered bonds.
Van der Wa
REGIOSELCTIVE, STEREOSPECIFIC AND STEREOSELCTIVE Regioselective: a reaction that can produce two (or more) constitutional isomers (usually positional) but gives one of them in greater amounts than the other.
OH H2SO4 H3 C H3 C C CHCH3 major CH3 H2C CCH2CH
SOLUBILITY OF ORGANIC
COMPUNDS IN WATER
Organic compounds that have both hydrogen bond donors
and acceptors will be water soluble if they have 5 carbons or
less (more carbons if multiple H-bond donor acceptors
Examples of water soluble compound
e-1 DOT STRUCTURES AND LEWIS STUCTURES
1. Write down each atom, showing its valence
electrons. Assign valence (bonding number) to
2. Bond together continuously with single bonds
(one electron pair) all atoms with a valence greater
than one. In bondi
VSEPR UNITS, ORBITAL HYBRIDIZATION,
ELECTRONIC GEOMETRY and BOND ANGLES
Resonance structures involve lone pair e-1 and multiple bonds in alternative arrangements, thus the total number of lone pair e-1 and multiple bonds cannot change
Resonance is used to describe electron delocalization in molecules Reso
Lewis Acids, Lewis Bases, Electrophiles, and Nucleophiles Chemical reactions originate from the flow of electrons from an electron source to an electron sink. An important skill that aids one in predicating the outcome of chemical reactions is the ability
HOW TO RECOGNIZE OXIDATION-REDUCITON
Step 1: Write a half reaction showing just the organic reactant and
Step 2: Material balance.
1) Acidic or neutral conditions: balance oxygens with H2O