Organic Chemistry Chapter 8 notes
*** Two main types of hydration reactions
1- Acid Catalyzed Hydration
2- Hydroboration Oxidation
* ACH is usually specified by writing H3O+ above rxn arrow. It favors the Markovnikov product.
* ACH is not stereospecific, so we get a pair of enantiomers (major products) for each new chiral center created by the addition.
*** HBO is a two step procedure:
1- Hydroboration, often written "BH3.THF", the alkene is reacted with NaBH3 in an Organic Solvent (commonly THF). A complex trialkylborane is formed.
2- Often written "H2O2, NaOH". The trialkylborane is oxidized by "H2O2" in the presence of a base "NaOH". Final outcome is hydration of the alkene, but favoring the anti-Markovnikov product. The reason it favores anti-Markovnikov product is because H in BH3 is more electronegative than B, causing for H to attach to the more substituted Carbon.
* The mechanism of HBO is stereospecific, and results ONLY in syn addition.
Lindlar's catalyst + H2 -> Z (cis)
Na + NH3 -> E (trans)