Chapter 9 Alcohols


I.  GENERAL
	ROH - General formula - H is weakly acidic and O is somewhat basic.
	Primary, secondary and tertiary alcohols classified the same as carbocation
	Thus, RCH2OH is a primary alcohol R2CHOH is a secondary, etc.
II.  Nomenclature
	A.  IUPAC Names - Alkanol
		Number so that OH occurs at the lower number	
		Cyclic alcohols are cycloalkanols with OH assumed to be at carbon 1.
		Alcohols containing double and triple bonds are named using the ol  suffix 			on the alkene and alkyne ending, e.g. 2-penten-1-ol or 3-hexyne-2-ol.
		Hydroxy group sometimes used.  e.g.  HOCH2 [ hydroxymethyl group
		Alkanediols need to indicate where two OH groups are.
		Phenols - Parent aromatic alcohol
	B.  Radical system - alkyl followed by alcohol
		methyl alcohol (wood alcohol)
		ethyl alcohol (grain)
		isopropyl alcohol (rubbing alcohol)
III.  Physical Properties of Alcohols
	A.  Hydrogen Bonding Effect
		1.  B. P. 
		2.  Solubility	
			hydrophilic and hydrophobic 
	B.. Acidity of Alcohols
		1.  aliphatic alcohols (non-aromatic)
			a. pKa's range from 16 to 19. MeOH and EtOH about as acidic as 				water, but t-BuOH is considerably less acidic (pKa = 19!!)
		  	electron-withdrawing atoms or groups increases acidity
			ClCH2CH2OH (pKa = 14.3)  F3CCH2OH (pKa=12.4)
			b.  Preparation of alkoxides - require Na or K metal.
	C.  Acidity of Phenols - much more acidic than alcohols - resonance stabilization of 		phenoxide ion
		1.  nitro groups at the 2- and or 4-position increases acidity, e,g, pKa of 4-			nitrophenol is about 7.
		2.  Preparation - since phenol is so much acidic than water its conjugate 			base phenoxide ion can be easily prepared by treatment with aqueous NaOH. solutions 	
IV.  Synthesis of Alcohols
	A.  Review -
		1.  SN2 reaction of alkyl halides with OH-
		2.  Addition of HOH to alkenes
			H+/HOH, H2SO4 then water/heat
			oxymercuration:demercuration and hydroboration:oxidation
		3.  KMnO4 - dihydroxylation
	B.  Use of Organometallic Reagents
		1.  Types of Organometallic Reagents
			1.  Grignard RMgX
				a.  Preparation
			2.  Organolithium 
				a.  Preparation
		2.  Addition to Carbonyl Compounds
			A.  Addition to formaldehyde gives a primary alcohol
			B.  Addition to an aldehyde gives a secondary alcohol
			C.  Addition to a ketone gives a tertiary alcohol
			D.  Addition to a ester (other than formate) or acid chloride yields a tertiary 				alcohol with two identical groups.
			E.  Addition to a formate ester yields a secondary alcohol with two identical 				groups.
		3.  Other reactions of Organometallics
			A.  Corey-House Coupling
			B.  Unwanted side-reactions with compounds having acidic or unsaturated 				substituents.
	C.  Reduction fo Carbonyl Compounds
		1.  Reagents
			LAH (powerful, non-selective: reduces almost all unsaturated groups and reacts 			violently with water and other acidic compounds)
			NaBH4 (, mild, selective: reduces mostly ketones and aldehydes) and does not 			react violently with water and other acidic compounds)
		2.  Reduces aldehydes to primary alcohols
		3.  Reduces ketones to secondary alcohols
V.  Thiols RSH
	A.  More acidic and more nucleophilic than alcohols.