Alcohol as a Nucleopnlle is CH3CH2C HH O: R—X ROH is weak nucleophile RO- is strong nucleophile Newo-c bond forms, o-H bond breaks Chapter 11
CH3CH2CH2 C H H Br O H H Chapter 11 11 Alcohol as a Nucleophile • ROH is weak nucleophile • ROis strong nucleophile • New O-C bond forms, O-H bond breaks. => C O H R X
CH3CH2CH H Alcohol as an Electrophile HH H OH- is not a good leaving group unless it is protonated, but most nucleophiles are strong bases which would go-O remove H Convert to tosylate (good leaving group)to C-Nuc bond forms react with strong C-o bond breaks nucleophile( base) Chapter 11 12
CH3CH2CH2 C H H Br O H H Chapter 11 12 Alcohol as an Electrophile • OHis not a good leaving group unless it is protonated, but most nucleophiles are strong bases which would remove H+ . • Convert to tosylate (good leaving group) to react with strong nucleophile (base) => C O H + C-Nuc bond forms, C-O bond breaks
CH3CH2CH H H Formation of Tosylate ester HH H-O:④ :O: O=S=0 O=S=0 CH CH p-toluenesulfonyl chloride ROTS TSCI, tosyl chloride' a tosylate ester Chapter 11 13
CH3CH2CH2 C H H Br O H H Chapter 11 13 Formation of Tosylate Ester p-toluenesulfonyl chloride TsCl, “tosyl chloride” C O H CH3 S Cl O O N CH3 O S O H O C CH3 S O O O C ROTs, a tosylate ester =>