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Ch. 1: Bonding, Resonance, and Molecular Geometry

DAT Organic Chemistry Outline

Chapte Chapterr 1: Bonding, Resonance, and Molecular Geometry Lesson 1.1 – Molecular Bo eome Bonding nding G eome metry try and Hybri Hybridiz diz dizat at ation ion Elect ctron Ele ct ron Domains Dom ains

Geometry Geom etry

Bond Angle Ang le

Hybridization

2

Linear

180

sp

3

Trigonal planar

120

sp2

4

Tetrahedral

109.5

sp3

Lesson 1.2 – Con Condens dens densed ed Form Formula ula ulas sa and nd Lin Line e-Bond Formulas

Lesson 1.3 – Si Sig gma an and dP Pii Bond onds s bond Type of covalent b ond

Number bonds Num ber of bo nds

Single bond

one sigma ( σ)

Double bond

one sigma ( σ) + one pi ( π)

Triple bond

one sigma ( σ) and two pi (π )

Lesson 1.4 – Or Orbital bital Hybri Hybridiza diza dization tion

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Ch. 1: Bonding, Resonance, and Molecular Geometry

DAT Organic Chemistry Outline

Lesson 1 1.5 .5 – Re Res son onan an ance ce S Sttruct uctu ure res s

Definition There are some molecules that have pi electrons that can move around from one atom to another. For example, the following molecules (A and B) are both different forms of acetate:

Structures A and B are called resonance structures (or resonance contributors). In reality, ace acetate tate actually exists somewhere in-between A and B, with the – charge being shared equally by the two oxygens. Resonance Rules When drawing different resonance st strructu turres, remember: Only elec electrons trons mov move. e. lectrons trons, lone-pair electrons, or negative charges can move. Do 1. Specifically, only pi e lec NOT move atoms. carbocations tions. 2. You CAN move electrons toward or into an atom that does NOT have a full octet, such as carboca 3. If an atom already HAS a full octet, then you can move electrons into it ONLY IF you push electrons out the opposite side (electrons in, electrons out). bonds ds. 4. Do not move or break sigma bonds, only pi bon Determining Greatest Resonance Contributor 1. The most stable resonance st strru cture will have a full octet on every atom. 2. The most stable resonance st strru cture will have the smallest possible number of charges. strru cture will have negative charges on the most electronegative atoms and 3. The most stable resonance st positive charges on the least electronegative atoms.

Lesson 1.6 – Ne Newman wman Pro Projectio jectio jections ns

Order of stability in Newman Projections from most to least: Staggered > Gauche > Eclipsed (most stable)

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(least sta stabl bl ble e)

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Ch. 1: Bonding, Resonance, and Molecular Geometry

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Lesson 1.7 – Cy Cyclo clo cloalk alk alkan an anes es an and dR Ring ing Stra Strain in

Cyc Cycloal loal loalka ka kanes nes are alkanes that are cyclic –in other words, ringed alkanes, or alkanes with rings in them. Cyclohexane is the most stable cycloalkane.

con n forma formati ti tions ons of cyclohexane (follow along!): How to draw chair co

Equatori atori atorial al Axia Axiall vs. Equ

• •

Equ Equatori atori atorial al positions are more stable (lower energy) than axial for larger groups because of 1,3-diaxial interactions. Placing the lar largest gest substituents in the equatorial positions will usually achieve the greatest stability in cyclohexane rings.

Trans vs. Cis cyclohexanes Cis – two substituents going in same direction Trans – two substituents going in opp opposite osite directions Cl

Cl

Cl

Cl

Cl

Cl

Cl

Cl

cis-1,2-dichlorocyclohexane

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cis-1,2-dichlorocyclohexane

trans-1,2-dichloro- trans-1,2-dichlorocyclohexane cyclohexane

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Ch. 2 – Acids and Bases

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Chapte Chapterr 2: Acids and Bases Lesson 2.1 – Acid Acid--Bas Base e De Definitions finitions

• •

A Lewis a acid cid is a substance that accepts el electro ectro ectrons ns. A Lewis base is a substance that donates ele elect ct ctron ron ronss .

Lesson 2.2 – Con Conjuga juga jugate te B Bas as ase e-Aci Acid dR Relat elat elationsh ionsh ionship ip and pH Scal Scale e

• •

acid d, the weaker its conjugate bas base e. The stronger the aci The stronger the base, the weaker its conjugate ac acid. id.

↑ KA = • •

↓ pKA =

↑ acid sstrength trength

acid d. The more stable/weaker the conjugate base, the stronger the aci The more stable/weaker the conjugate ac acid id, the stronger the base.

pKas for Org Organic anic Com Compoun poun pounds ds

Lesson 2.3 – Ra Ranking nking A cids an and d Base Bases s with CARDIO (Ch (Charge) arge)

If all other factors are the same (or close to the same), then: • •

The more posit positively ively ively--char charg ged the compound = the more acidic negatively ively ively--cha charged rged the compound = the more basic The more negat

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Ch. 2 – Acids and Bases

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Lesson 2.4 – Ra Ranking nking A cids an and d Bases with CA CARDI RDI RDIO O (A (Atom tom tom))

If all other factors are about the same, then hydrogen’s acidity increa increases ses as the atom that it’s bonded to: • •

goes left left--to-ri rig ght ac acrross a ro row w on the periodic table (increasing electronegativity) goes down a co on the periodic table (increasing size) column lumn

Lesson 2.5 – Ra Ranking nking A cids an and d Bases with CARDIO ((Re Re Resonan sonan sonance) ce)

• •

base e, the stronger the aci acid d The more stable the conjugate bas The more stable the conjugate aci acid d, the stronger the ba base se

Resonance increases the stability of charges, therefore a resonance resonance--st sta abililiized con onjjugate base will be a stro stron n ger acid.

Lesson 2.6 – Ra Ranking nking A cids an and d Bases with CARDIO ((D D ipo ipoll e In Induction) duction)

• •

Ele Elect ct ctron ron Withdr Withdrawing awing groups incr increase ease acidity Ele Elect ct ctron ron Don Donating ating groups decr decrease ease acidity

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Ch. 2 – Acids and Bases

DAT Organic Chemistry Outline

Lesson 2.7 – Ra Ran n king Acids and Ba Bases ses with C CARDIO ARDIO (Orbita (Orbitall s)

If all other factors are about the same, then acidity follows the below trend: (less acidic) •

H–sp 3 atom

<

H– sp2 atom

<

H– sp atom (more acidic)

SS-orb orb orbitals itals tend to be more electronegative, so the more “s-character” an atom has, the stronger the acid.

Lesson 2.8 – Acid an and d Bas Base e Rev Reviiew

How to Sort Acids and Bases by Strength First, convert the acid to its conjugate base. 1. Charge – Positively charged compounds are typically more acidic, negatively charged compounds are typically more basic. 2. Atom – The more electronegative/larger the atom with a negative charge, the more acidic the hydrogen is. 3. Resonance – The more resonance-stabilized the conjugate base, the stronger the acid. 4. Dipole Indu Induct ct ction ion – Electron withdrawing groups increase acidity, electron donating groups decrease acidity. 5. Orbitals – The more s-character an atom has, the more electronegative it is, and the more acidic hydrogen’s bonded to it will be. i.e. sp3 < sp2 < sp

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Ch. 2 – Acids and Bases

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Lesson 2.9 – pH an and d Ami Amino no Ac Acids ids

To determine the structure or charge of any amino acid: •

If the pH of the so solut lut lution ion is LOWER than th the ep pKa Ka of the functional group, the functional group will be

protonated. •

If the pH of the so solut lut lution ion is HIGHE HIGHER R tha than n th the e pKa of the functional group, the functional group will be deprotonated.

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Ch. 3 – Nomenclature

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Chapte Chapterr 3: Nomenclature Lesson 3.1 – IUPAC Basic Basics sa and nd Nam Naming ing Alkan Alkanes es

Naming Alkanes 1. Find the parent chain, the longest carbon chain. If two possible parent chains have the same length, but different substituent numberings, pick the one with the smaller substituent number at the first point of difference. chain ain and match that number to the name from our 2. Count the number of carbon atoms in the parent ch earlier chart (methane, ethane, propane, etc.) parent nt cchain hain) in whichever direction gives 3. Identify and number the substituents (appendage dangling off the pare them the lowest number. 4. Write the name as a single word with the substituents in alphabetical order.

Lesson 3.2 – Nami Naming ng Cy Cycloalk cloalk cloalkanes anes and Alk Alkyl yl Ha Halides lides

Naming Cycloalkanes 1. When there are two substituents on a cyclic molecule, their direction must be indicated with prefix “cis”, meaning “same side”, or “trans”, meaning “opposite sides”.

2. If there are more than two substituents, “cis” and “trans” are no longer enough, and these substituents must be named with their stereochemical configurations (R/S system).

Naming Alkyl Halides When naming alkyl halides, we follow the same rules for naming alkanes, except that we use prefixes “fluoro-“, “chloro-”, “bromo-”, or “iodo-”, to identify each halogen substituent. Alternatively, we may use suffixes “-yl fluoride”, “-yl chloride”, “-yl bromide”, or “-yl iodide”.

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Ch. 3 – Nomenclature

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Lesson 3.3 – Nami Naming ng Alk Alkenes enes an and d Alky Alkynes nes

Naming Alkenes 1. Use suffix “-ene ” instead of “-ane ”. 2. Add a number at the start of the double bond. 3. Add prefixes “cis” or “trans” for alkenes with different priority substituents, and at least one hydrogen on either side of the alkene. 4. If all substituents are different, use the E/Z naming system, where E = highest priority substituents on opposite sides, and Z = highest priority substituents on the same side.

Determining Priority 1. Highest atomic number = highest priority. 2. If there’s a tie, keep going to adjacent carbons until you break the tie. 3. Multiple-bonded atoms are counted as the same number of single-bonded atoms:

Naming Alkynes 1. Use suffix “-yne ” instead of “-ane ”. 2. Add a number at the start of the triple bond.

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Ch. 3 – Nomenclature

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Lesson 3.4 – Nami Naming ng Alc Alcoho oho ohols, ls, E Ethers thers thers,, an and d Am Amines ines

When naming alc alcohols ohols, we follow the rules for naming alkanes, except: 1. The parent chain is now the longest chain that has the hydroxyl group, even if there are longer carbon chains available. 2. Number the carbon chain in the direction that gives the smallest number to the carbon bonded to the hydroxyl group. 3. Hydroxyl groups are higher priority than cycloalkanes, amines, alkenes, ethers, and alkyl halides, so they must be numbered according to the lowest-number carbon that is bonded to the hydroxyl group. 4. Change suffix “-e ” to “-ol ”. ethers: When naming ethers 1. Name the two alkyl groups as substituents with “ether” at the end:

2. Consider the longest carbon chain to be the parent chain and the alkoxy group to be a substituent:

primary ry amin amines es , add the suffix “amine” to the name of the organic substituent. When naming prima

Symmetrical and secondary amin amine es are named by adding “di-” or “tri-” to the alkyl group:

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Ch. 3 – Nomenclature

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Lesson 3.5 – Nami Naming ng Al Aldehy dehy dehydes des a and nd K Keton eton etones es

When naming ald aldehydes ehydes, we follow the rules for naming alkanes with the addition of two rules: 1. We number the parent chain in the direction that gives highest priority (lowest number) to the aldehyde (carbonyl) carbon. 2. We replace “ e” with “ al ”.

When naming ketones, we follow the same rules for naming alkanes, except: 1. Similar to aldehydes, the parent chain must be chosen with priority given to the ketone (carbonyl) carbon. 2. Replace the “e ” with “one”. 3. The carbonyl carbon in a cyclic ketone is assumed to be the #1 carbon.

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Ch. 3 – Nomenclature

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Lesson 3.6 – Nami Naming ng Ca Carboxy rboxy rboxylic lic Acid Acids sa and nd Derivative Derivatives s

When naming carboxylic ac acii ds, we follow the rules for naming alkanes, except: 1. We number the parent chain in the direction that gives the highest priority (lowest number) to the carboxylic acid group. acid d”. 2. We replace “ ane” for “ oic aci

When naming aci acid dh halides alides: halide de ”. 1. Follow the same rules as for carboxylic acids, and change the suffix to “ oyl hali

When naming ester esters s: 1. The alkyl group attached to the ester oxygen gets listed first with the suffix “ yl ”. The parent chain then follows. 2. The parent chain starts at the carbonyl carbon and is counted moving away from the ester oxygen. Parent chain’s suffix is replaced with “ oate ”.

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Ch. 3 – Nomenclature

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Lesson 3.6 – Nami Naming ng Ca Carboxy rboxy rboxylic lic Acids an and d Deri Derivativ vativ vatives es (Cont (Continued) inued)

When naming amid amide es, we follow the same pattern of naming for ester esters s , except: 1. Any alkyl groups attached to the nitrogen gets listed as “N-methyl”, “N-ethyl”, “N-propyl” etc. 2. The parent chain starts at the carbonyl carbon and is counted moving away from the amide nitrogen.

acid d an anhydrides hydrides: When naming aci 1. Determine the length of the chain on either side of the bridging oxygen. 2. List both lengths alphabetically, replacing each suffix “ e ” with “ oic”. 3. Write “ anh anhydride ydride” at the end of the name.

nitriles s, follow the same rules for naming alkanes, except: When naming nitrile 1. The parent chain is the longest carbon chain that involves the nitrile carbon. 2. Number the parent chain in the direction that gives the smallest number to the nitrile carbon. 3. Add the suffix “nitrile” to the parent name.

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Ch. 3 – Nomenclature

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Lesson 3.7 – Nami Naming ng Ar Aromat omat omatii cs

When naming substituted ben benzz enes: 1. Identify the pare parent nt cchain hain, which is the benzene containing the highest-priority functional group. That par parent ent chain n nam name e. chain is the parent chai 2. The carbon atom in the ring that is attached to the priority functional group is numbered as carbon #1. 3. Number around the ring in whichever direction (clockwise or counterclockwise) that gives the lowest number at the first point of difference. 4. If the numbers are the same in both directions, pick the one that gives the lower number to the substituent that is alphabetically first.

Lesson 3.8 – Nami Naming ng Po Polyfu lyfu lyfunctio nctio nctional nal Com Compound pound pounds s

poly--fu fun n ctional compounds: When naming poly 1. You must identify the highest-priority functional group. The paren parentt cha chain in containing this functional group is the parent chain nam name e. chain n and its functional group, follow the naming rules for that particular 2. Once you identify the parent chai functional group. All other functional groups in the molecule are considered and named as substituents. Priority of Functional Groups

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Ch. 3 – Nomenclature

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Lesson 3.9 – Nami Naming ng Sp Spiiro an and dB Biicyc ycllic Al Alk kan ane es

Spiro Alkanes IUPAC names for spiro alkanes have the format spiro[a.b]pare spiro[a.b]paren n t name. tota total l 1. Count the number of carbons across the entire molecule. This tells you the alkane parent name that goes at the end. 2. Count the number of carbons to the left, and to the right of your spiro-carbon center. These numbers are a and b in your IUPAC name, listed from lowest to highest. 3. Write your final IUPAC name as spiro[a.b]parent na name me.

Bicyclic Alkanes bicyclo[a. yclo[a. yclo[a.b.c]pa b.c]pa b.c]parent rent na name me. IUPAC names for bicyl bicylic ic alka alkanes nes have the format bic tota total l number of carbons across the entire molecule. This tells you the alkane parent name that 1. Count the goes at the end. 2. Count the number of carbons to the left, and to the right, and above your bridgehead carbons. These numbers are a, b, and c in your IUPAC name, listed from highest to lowest. 3. Write your final IUPAC name as bicyclo[a.b.c]parent name.

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Ch. 4 – Stereochemistry

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Chapte Chapterr 4: Stereochemistry Lesson 4.1 – Isomers

Constitutional Isomers vs. Diasteromers vs. Enantiomers •

isomers. mers. Molecules that have the same chemical formula, but a different arrangement of the atoms, are iso

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Ch. 4 – Stereochemistry

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Lesson 4.2 – Chir Chiral al Cent Centers ers enter is a carbon center that contains four unique substituents. A chirality cce

When using the R,S nam naming ing sy system stem: 1. Find your stereocenter atom. 2. Prioritize the four appendages coming off the stereocenter atom using the Cah Cahn n -Ing Ingold old -Prelog system. a. Highest priority = highest atomic number. b. If there’s a tie, keep going out in both directions, one by one, until the tie is broken. 3. Number your substituents 1, 2, 3, 4 (1 = highest priority, 4 = lowest priority) 4. Direct the lowest-priority substituent three-dimensionally away from you. 5. Make a circle from substituent 1 to 2 to 3. a. Clockwise = R b. Counterclockwise = S Examp Examples: les:

Chiral carbon

S

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Enantiomers

S

R

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Ch. 4 – Stereochemistry

DAT Organic Chemistry Outline

Lesson 4.3 – Diast Diastereo ereo ereomers mers

There are three types of diastereomers: 1. Cis/trans isomers of ringed compounds:

2. Cis/trans or E/Z isomers of alkenes: H3C CH3 trans-but-2-ene or (2E)-but-2-ene

H3C

CH3

cis-but-2-ene or (2Z)-but-2-ene

3. Stereoisomers with mu...