Organic Chemistry 1 Reagents

Reagents, their mechanisms, and the types of products they form Includes reagents for alkane, alkene, and alkyne reactions as well as multistep reagentsRecommended to fully know functional groups by name for this setTheres another set with nucleophile stuff/E1/E2/SN1/SN2 info. When I say carbonyl I mean ketone or aldehyde. Sorry a lot of the cards are long! It is very hard to make a flashcard for organic chemistry mechanisms with multiple steps w/o breaking up questions but I want to keep all the info for each reagent together. Plus these notes are mostly for myself so I include extra reminders

subst: substituted
X: denotes a halide atom in formula (Br, Cl, I, etc)
LG: leaving group; LG is usually same atom as X
Nu: nucleophile
Ele: electrophile
str: strong
w: weak
e-: electron
lp: lone pair
SM: starting molecule/material
config: configuration (R vs S)

Abbreviations I use- reference card if you need it
these notes are mostly for myself so I include extra reminders on some
sorry some of the cards are long, hard to do mechanism and I dont wanna break it up

What is a Markovnikov product? What type of reactions are they involved in?

Markovnikov reactants attach substituent to more subst C
addition reactions to an alkene

What is a Zaitsev product?

Zaitsev forms more subst alkene

What is Hofmann product and what causes it when forming an alkene?

Hofmann forms less subst alkene when using a bulky base or a bad LG

Identify the reagents and describe the mechanism that occurs during acid-catalyzed hydration of an alkene

(reagents: cat. acid (H+, H2SO4, etc) and water/H2O)
Markovnikov addition of an OH to form an alcohol

Identify reagents used in oxymercuration-demercuration of an alkene and describe the product formed. (hint: oxyMERCuration)

reagents: 1. Hg(OAc)2/THF-H2O 2. NaBH4, OH
multistep mechanism for Markovnikov addition of an alcohol

Identify the reagents used for acid cleavage of ethers (R-O-R') into two alkyl halides (+H2O) and briefly describe the steps of the mechanism
note: different product(s) formed if reactant is Ph-O-R

reagent: strong acid (HX)- HBr, HCl, HI
mechanism steps: protonate O -> break C-O between more subst R group, X attacks cation -> protonate OH- -> H2O acts as LG and X attacks less subst R'

What products form when a phenyl ether (Ph-O-R) reacts with a strong acid (H-X)? (one product is the same as acid cleavage of a regular ether)

forms alkyl halide of R substituent (X-R) and phenol (Ph-OH)
(cannot cleave sp2 Ph-O bond, protonates O instead)

Describe the reaction when H2, Pd/C reacts with an alkene. What is the name/mechanism of reaction?

reduces pi bond to single bond
mechanism: (catalytic) hydrogenation- adds a hydrogen to each C on pi bond

Describe the reaction when H2, Pd/C reacts with an alkyne.

reduces triple bonds to single bonds

When will pi bonds not be reduced under normal hydrogenation/addition conditions? What conditions can reduce these bonds?

when they form an aromatic ring
can be reduced via high temp/pressure w/ metal catalyst

Identify the reagents needed to form a diol from an alkene via anti-addition (two steps, two reagents).

reagents: 1. m-CPBA forms epoxide ring 2. H3O forms trans diol

(OR st 1 can be R-CO3H)

What reagents can be used to form an epoxide ring from an alkene? (two options)

m-CPBA OR (1. Br2, H2O 2. NaOH (str base))

What reagent(s) can be used to form a trans diol from an epoxide ring?

H3O

Describe the mechanism and product that forms when an alkene reacts with HBr (1 equiv and 2 equiv)

Markovnikov addition of Br to alkene
1 Br (1 equiv) or 2 Br (2 equiv) on same C

Describe the mechanism and product that forms when an alkene reacts with NBS (1 equiv and 2 equiv)

may form radical intermediate
Markovnikov addition of Br to *allylic/benzylic* carbon
adds 1 Br (1 equiv) or 2 Br (2 equiv)

ALWAYS check products to see if a ______ was formed after completing a reaction unless _____

stereocenter!!!
UNLESS config is inverted by SN2

Describe the common mechanism undergone by ROOR which influences reaction products

radical mechanism (initiation, propagation, termination)
less subst products are often formed

Describe the product formed when an alkene reacts with HBr, ROOR

anti-Markovnikov addition of Br on alkene

What mechanism occurs when reagents Br2, hv react with an alkane? Does it form a more or less subst product?

Radical bromination- initiation, propagation, and termination of radicals
forms more subst product

What do reagents H2, Lindlar's catalyst do when reacting with an alkyne?

reduces triple bond to CIS double bond

What do reagents Li, NH3 do when reacting with an alkyne?

reduces triple bond to TRANS double bond

What effect do bulky bases usually have on product formation? What mechanism usually occurs when they are a reagent?

bulky bases make LESS subst product
usually via E2

What product forms when an alkyl halide reacts with a bulky base as the only reagent?

formation of the less subst alkene

Describe the reaction that occurs when an alkane w/ an OTS group (alkyl tosylate) reacts with a salt (Na attached to an anion such as Br, OH, CN, etc)

OTS acts as LG, then anion attacks via SN2
results in inverted configuration

What reagent forms the Hofmann product when reacting with an alkene?

bulky base (KOtBU)

Identify the reagent used to form the Zaitsev product (more subst alkene) from an alkyl halide

NaOH (or other small strong base)

What product forms when NaOH reacts with an alkyl halide?

OH replaces LG (usually Br) to form an alcohol

What product forms when an alcohol reacts with TsCl, Py?

OH on alcohol becomes OTS

Identify reagents used and mechanism for hydroboration-oxidation of an alkene
(forms less subst alcohol from an alkene)

1. BH3 2. H2O2, NaOH, H2O
anti-Markovnikov addition of OH to alkene

an alkyl halide can replace its halide with a substituent group using reagents that follow a similar formula. These reagents have the general formula ___-____
(first blank is constant, 2nd is variable)

Na - substituent group (OH forms alcohol, OMe forms ether, SH forms thiol, CN forms nitrile)

What differences (two) occur in products when using NBS instead of Br2/hv or HBr.

NBS adds to the allylic or benzylic carbon
pi bond is still present after NBS via radical mechanism

What type of alchohol cannot be oxidized to form an aldehyde/ketone?

tertiary alcohols

What reagents can be used (four options, sorry) to form a ketone from a secondary alcohol? What type of reaction is this?

reagents: (PCC w/CH2Cl2 or solvent), (chromic acid: Na2Cr2O7, H2SO4, H2O), (DMP), or (1. DMSO, (COCl)2 2. NEt3)
oxidation of an alcohol to a carbonyl

What reagents can be used (thee options) to form an aldehyde from a primary alcohol? What type of reaction is this?

reagents: (PCC w/CH2Cl2 or solvent), (DMP), or (1. DMSO, (COCl)2 2. NEt3)
oxidation of an alcohol to a carbonyl

What functional group forms when chromic acid reacts with a primary alcohol? (different from other alcohol oxidation reagents; hint: acid)

carboxylic acid

Where does the C=O bond form in an oxidation reaction of an alcohol via PCC/DMP/DMSO/Chromic acid?

forms where the C-OH bond was on SM

What reaction occurs when a primary or secondary alcohol (never tert) reacts with (SOCl2, Py) or (PBr3, ether)?

halide (Cl or Br) replaces OH on alcohol with an inversion of config due to back attack

What product forms when an alkyl halide reacts with a bulky base as the only reagent? What if it is a small base?

bulky base: forms less subst alkene
small base: forms more subst alkene

Identify reagents used to reduce a ketone to a secondary alcohol. What type of reaction is this?

(NaBH4, EtOH) OR (1. LiAlH4 2. H3O)

reduction of ketone to form 2° alcohol

Identify reagents that can be used to reduce an aldehyde to a primary alcohol (two options). What type of reaction is this?

reagents: (NaBH4, EtOH) OR (1. LiAlH4 2. H3O)

reduction of aldehyde to form 1° alcohol

Briefly describe the mechanism used to reduce ketones/aldehydes when (NaBH4, EtOH) OR (1. LiAlH4 2. H3O) is the reagent

reduce pi bond to single bond, H attacks charge on C, protonate O
C=O becomes C-OH

What is a Grignard reagent (general chemical formula) and how is it synthesized from a halocarbon (include reagent(s) to form)?
"Mg insertion"

synthesis reagents: 1 equiv Mg, ether solvent (Et2O or THF) inserts Mg between C-X bond to form C-MgX
formula: carbon chain attached to an MgX compound (R-MgX)

What are organolithium reagents (general chemical formula) and how are they synthesized from a halocarbon (include reagent(s) to form)?
"Lithium-Halogen exchange"

synthesis reagents: 2 equiv Li, Et2O
Li replaces halogen on halocarbon to form Li-R, Li-X is formed as a byproduct
general form: R-Li, usually BuLi

Describe the mechanism and product that forms when a Grignard (R-MgX) or organolithium (R-Li) reagent reacts with a ketone.
(step 2. H2O)

1. C=O oxygen takes pi e- from bond, R group from reagent attacks C
2. protonation of O via H20
forms an alcohol with an added R group

What reagents can be used to increase the carbon chain? (2 options, 2 steps mechanism)

1. Grignard reagent OR organolithium

2. H2O

What two products react with H2SO4 to form a symmetrical ether?

two primary alcohols

What reagent(s) can be used to form a diol from an alkene via syn addition? (two options)

(1. cat OsO4 2. H2O2)
OR (KmnO4, NaOH cold)

Identify the reagents for the mechanism:
a cycloalkene pi bond is cleaved to form an alkane —> functional group forms on each C from cleaved bond
if primary C- aldehyde; secondary- ketone

1. O3 2. DMS (AKA di-methyl sulfide, Me2S)

What is TsCl, (pyridine or imidazole) useful for when reacting with alcohols? What changes on the product compared to SM?

forming a better LG by forming a sulfonate ester
OH becomes OTs

OTs is a particularly good LG for _____ reagents

organometallic (Bu-Li, etc)