exam 2 Chapter 10;/11 Flashcards
Williamson Ether Synthesis
SN2
-between R-O- (nu) and R-x (e)
1. deprotonate o
2. O- will attack C-X bond and new C bond is created
Converting Alcohols to Good LG
HX addition
-Turns OH into whatever X is
-not a good option
PBr3 or PCl3
-works with methyl, 1, 2 alcohols
-inversion of sterochem
-OH still turns into whatever cl or br
Tosylate
-No inversion of stereochem
-Oh turns to TSO
—-After OTS or BR conversion to new group there is Inversion
Epoxide RXN under acidic conditions
H+ protonates the O and the NU will attack the more substituted epoxide C
-H-CL
-H-Br
-H-I
Epoxide Rxn With Alcohol as the NU
-H2SO4 and R-OH
-H+ protonates the O
-R-oh acts as Nu and opens the epoxide
-when alcohol is added RO is added (NOT OH)
Epoxide RXN with Neucleophile
-non acidic first step
-HO-, RO-, RS, H2N, CN, r-c-c, R
-Nuc attacks less substituted C
-requires H in step 2 to protonate R-O-
-attacks opposite the leaving group
Alkylation
-No rxn with internal Alkynes
-Need Strong base and Br-R
-NaNH2 and NaH reacts with H and - attacks the carbon bonded to BR which results in the carbons added to the alkyne
Carbonyl alpha-carbon alkylation
-A C attached to a carbonyl is an alpha carbon
-H bonded to the alpha carbon and alpha H
-Alpha H are relatively acidic
-forms enolate
Bases Used in Enolate Formation
-LDA, Li-N THF (strong and bulky make 100% enolate formation)- attacks less sub a-hydrogen
-NaOH, NaOET, NaOR (less strong, give small % of enolate) attacks more sub
Enolate Alkylation
1) use base to form Enolate
2) Add R-x (E) (puts R at alpha position)
Kinetic-Product that is formed faster (bulky base attacks more acceddible H)
Thermodynamic- Equilibrium favors more stable enolate (Less strong bases)
Alpha- Halogenation
X2 and base mix
-all apha hydrogens get replaced by X
-If u use acidic conditions with X2, X will be added to alpha Carbon only once
