more reaction mechanisms

hydrohalogenation

add h-x

solvent= CH3COOH

mark

allows for rearangment

yeilds: breaks double bond and places halogen on most substituted carbon

Acid-Catalyzed Hydration

add H20

solvent: H2SO4

mark

allows rearangment

yeilds. breaks doublebond and places OH on more substituted carbon

Halogenation

add X2 (Cl, or Br)

spolvent (CH2Cl2)

NO regeoselectivity

anti-stereospecific

yeilds: breaks double bonds and places X on both sites

creates bridged halonuim ion PREVENTS rearangement

Halohydrination

add X2+H2O (HOX)

solvent (H2O)

Mark

anti-stereospecific

yeilds: mark addition of OH and X

creates halonium bridge PREVENTS rearrangement

Oxymercuration/Reduction

part 1: add Hg(OAc)2 in H2O

part 2: NaBH4

solvent H2O

mark

anti-sterospecific

creates bridge PREVENTS rearrangement

yeilds: mark addition of OH

Hydroboration/Oxidation

1: add BH3, THF

2: add H2O2, NaOH

solvent THF

Anti-mark

syn-stereospecific

yeilds anti mark addition of OH

usually to a termally alkene

Oxidation with Osmium tetroxide

1. add OsO4

2. NaHSO3 and H2O

no regio specificity

syn stereo specific

yeilds addition of 2 OH's on double bond sites

Oxidation with Ozone

1. add O3

2.(CH3)2S

no regio

no stereo specificity'

yeilds: splits double bond and puts a double bonded Oxygen, creates aldehyde

also yealds DMSO

metal catalyzed Reduction of Alkenes

1. H2 + solution of Pd (or any metal cation)

conditions: 25C 3atm

no regio

syn-steroSELECTIVE

yeilds: breaks double bond and hydrogenizes sight

NOTE: could also go half way then back resulting in a shift of the double bond

terminal Alkyne acid reaction

1. sodium hydride, NaH, or LDA

yeilds: A/B reaction

Alkylation of Alkyne Anions

terminal alkyne + terminal halogen7

yeilds terminal alkynes.

Elimination with

Alkyne Anions

terminal alkyne anion + 2nd or 3rd degree halide

yeilds alkyne and creates a double bond where the halide was

Alkynes from Alkenes

vicinal haloalkanne (can be formed from alkene by treating with X2) + 1 equivilance of NaNH2 per pi bond formed plus one if new pi bonds terminal

yeilds alkyne from alkene or vicinal haloalkane

requires NH3 and a -33C temp

considered an elimination reaction

can form an allene in stead soemtimes

Electrophilic Addition of X2 to alkynes

alkyne + X2

solvent= CH3COOH, LiBr

antistereoselective

yeilds vicinal haloalkene

Electrophilic Addition of HX to alkyne

alkyne +HX

mark

yeilds mark addtion of X (alkene

can be done twice to yeild alkane

hydroboration oxidation of internal allkyne

1. BH3

2. H2O2, NaOH

syn-stereoSELECTIVE(H and B)

yeilds: enol then ketone

hydroboration oxidation of Terminal allkyne

1. (sia)2BH

2. H2O2, NaOH

stereoSELECTIVE

regioselective (B(Sia)2 always attaches to end)

produces enol then aldehyde

`Acid-catalyzed hydration of alkynes (with mercury salt)

H2O

slovent: H2SO4+HgSO4

mark kinda

creates mercurium bridge

yields enol then ketone REGARLESS of terminal or internal alyne

catalytic reduction of Alkynes (no lindlar)

2H2+ Pd,Pt or Ni (3atm)

syn stereoSELECTIVE

reaction goes twice to yeild alakne

catalytic reduction of Alkynes

(lindlar)

H2 + lindlar catalist (Pd/CaCO3 poisoned with PbCO3.)

syn-stereoSELECTIVE

yeilds (Z)-Alkene

Hydroboration-Protonolysis

1. internal alkyne +BH3

solvent THF

2. Tretment of product with CH3COOH