CHEM 2301 Chapter Notes - Chapter 11: Organoboron Chemistry, Hydroboration, Tautomer
Document Summary
H2o elements add to the triple bond. Initial addition product is an enol which is unstable and rearranged to a product with a carbonyl group (co double bond) Ketone - a carbonyl compound with 2 alkyl groups bonded to the co double bond. Terminal alkynes need additional hg2+ catalyst - hgso4. Tautomers = constitutional isomers that differ in location of a double bond and a h. 2 are in equilibrium with each other. Enol tautomer has oh bonded to c=c. Keto tautomer has c=o and additional ch bond. Eq favors jeto because c=o is stronger than c=c. Tautomerization in acid: protonation of the enol c=c with acid add h+to make resonance stabilized carbocation, loss of proton forms carbonyl group. Hydroboration oxidation convers alkyne to carbonyl compound. Overall result is addition of h2o to triple bond. Hydroboration oxidation of internal alkyne forms a ketone. Hydroboration of terminal alkyne added b to the less substituted terminal c.
