ORGANIC CHEMISTRY Chapter 7 7. 11 The Acidity of Terminal Alkynes Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 7 7.11 The Acidity of Terminal Alkynes
ORGANIC CHEMISTRY Chapter 7 Sp CH≡CHCH2=CH2CH3=CH3 K p 25 50 Relative basicity Ch=C CH2=CH CH3-CH Relative acidity H2O>ROH >RC=CH >NH3 >CH2=CH2> CH3-CH pka15716-1725 38 44 50 Relative basicity OH <Ro< RC=C NH, CH,=CH CH3-CH, Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 7 CH CH CH2 CH2 CH3 CH3 sp sp2 sp3 pKa 25 44 50 Re CH C < < CH2 CH CH3 CH2 lative Basicity Relative Acidity H2O ROH RC CH NH3 CH2 CH2 CH3 CH3 > > > > > pKa 15.7 16-17 25 38 44 50 Relative Basicity OH < < RO RC C < NH2 < CH2 CH < CH3 CH2
ORGANIC CHEMISTRY Chapter 7 o acetylenic hydrogens can be deprotonated with relatively strong bases(sodium amide is typical 2Na NH3(liq 2NanH H2 NH3(0 NaNH CH三CH+NaNH2-33 CH三CNa NaC≡CNa NH3() CH3C=CH NaNH 2 ChrC=cna 33 The products are called alkynides Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 7 Acetylenic hydrogens can be deprotonated with relatively strong bases (sodium amide is typical) 2Na + NH3(liq.) 2NaNH2 + H2 −40 CH CH + NaNH2 NH3(l) −33 CH CNa NaC CNa NaNH2 CH3C CH + NaNH2 NH3(l) −33 CH3C CNa The products are called alkynides
ORGANIC CHEMISTRY Chapter 7 RC≡CH+HOBr-RC≡CBr+H2O CH≡CH+Ag(NH3 AgC≡ CAgy white CH≡CH+Cu(NH CuC≡ CCu red Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 7 RC CH + HOBr RC CBr + H2O CH CH + Ag(NH3)+ AgC CAg white CH CH + Cu(NH3)+ CuC CCu red
ORGANIC CHEMISTRY Chapter 7 7.12 Replacement of the acetylenic Hydrogen atom of Terminal alkynes Department of Chemistry, Xiamen University
ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 7 7.12 Replacement of the Acetylenic Hydrogen Atom of Terminal Alkynes