Hoa huu co_ancol

HOÁ HỌC HỮU CƠ
Organic Chemistry
CHƯƠNG 10
ALCOHOLS & PHENOLS
Mendeleev
Hamilton
Hartree
GIỚI THIỆU CHƯƠNG
10.1. RƯỢU
10.1.1.DANH PHÁP & ĐỒNG PHÂN
10.1.2.CÁC PHƯƠNG PHÁP ĐIỀU CHẾ
10.1.3. TÍNH CHẤT
10.1.4.ỨNG DỤNG

10.2. PHENOL
10.2.1. DANH PHÁP & ĐỒNG PHÂN
10.2.2. CÁC PHƯƠNG PHÁP ĐIỀU CHẾ
10.2.3. TÍNH CHẤT
10.2.4. ỨNG DỤNG

DANH PHÁP
DANH PHÁP
5-methyl-2,4-hexanediol
2-methyl-4-phenyl-2-butanol
4,4-Dimethylcyclohexanol
trans-2-Bromocyclopentanol
LIÊN KẾT TRONG RƯỢU
Alcohols





IR spectrum of 1-hexanol (Fig 12.8)
Example: Mass Spectrum of Methanol (CH3OH)
CH3OH + e-  CH3OH+ + 2e-
CH3OH +  CH2OH+ + H
CH3OH +  CH3+ + OH
CH2OH +  H2 + CHO+
Chemical Properties
Alcohols as acids
Sterically hindered alcohols such as tert-butyl alcohol are less acidic (have higher pKa values)
stronger acids than terminal alkynes and primary or secondary amines
Alkoxides prepared by the reaction of an alcohol with sodium or potassium metal

H2O
H2S
H2Se
H2Te
CH4
SiH4
GeH4
SnH4
Hydrogen Bonding
1. Water, HF, and NH3 show unusually high bp.
2. Dotted lines depict bp if there were no H-bonding.
3. All others follow normal trend.
… extrapolation
HF
NH3
Hydrogen Bonding in Water
--
+
+
+
+
+
+
+
+
+
+
--
--
--
--
Hydrogen Bonding in Alcohol
-
+
+
+
+
+
-
-
-
-
Hydrogen Bonding and Boiling Point
Acidity & Basicity
Like water, alcohol can act as an acid or as a base.
acid
oxonium ion
base
acid
base
alkoxide ion
phenoxide ion
Conversion to Alkyl Halides
Hydroxyl groups are poor leaving groups
Reaction of Alcohols with HX
Tertiary alcohols: SN1
Conversion to Alkyl Halides
Conversion to Alkyl Halides
Conversion to Alkyl Halides
Conversion to Alkyl Halides
Primary Alcohols: SN2




Use of Lewis acids
Conversion to Alkyl Halides
Conversion to Alkyl Halides
Reaction of Alcohols with PBr3
Conversion to Alkyl Halides
Conversion to Alkyl Halides
Reaction of Alcohols with SOCl2
Leaving Groups
Tosylates (Ts), Mesylates (Ms), and Triflates (Tf): Leaving Group Derivatives of Alcohols
Sulfonates as Leaving Groups
Recall: SN2 inversion of configuration




Triflate anion is such a good leaving group that even vinyl triflates can undergo SN1 reaction
Synthesis of Ethers
Intermolecular Dehydration of Alcohol
This reaction occurs at lower temperature than the competing dehydration to an alkene
does not generally work with secondary or tertiary alcohols (elimination competes strongly)
Synthesis of Ethers
Mechanism
Williamson Ether Synthesis
Synthesis of unsymmetrical ethers
Recall: the alkyl halide (or alkyl sulfonate) should be primary to avoid E2 reaction, Substitution is favored over elimination at lower temperatures

Alkoxymercuration-Demercuration
Markovnikov selectivity
Reaction of Ethers
Acyclic ethers are generally unreactive, except for cleavage by very strong acids
Alcohol Protecting Groups
The protecting groups are used to protect primary alcohols from reacting
Added before the reaction and removed after
Base
Alcohol Protecting Groups
Silyl Ethers
Tert-butyldimethylsilyl (TBDMS)
Base = pyridine, imidazole



Removal: fluoride ion
Protection of Alcohol
“It often happens, particularly during synthesis of complex
molecules, that one functional group in a molecule
interferes with an intended reaction on a second functional
group elsewhere in the same molecule.” - p 682.
Trimethylsilyl (TMS) ether
Chlorotrimethylsilane
TMS ether
ROH is now blocked or protected!!!
Step 1: Adding Protection Group
+
Step 2a: Carrying Out Reaction
Step 2b: Carrying Out Reaction
+
Step 3: Removing Protection Group
+
CẢM ƠN SỰ THEO DÕI CỦA CÁC BẠN

CHÚC MỌI ĐIỀU TỐT ĐẸP