Select the keyword or phrase that will best complete each sentence. 1. anions are strong nucleophiles that open epoxide rings by an SN2 mechanism.

2. tautomers have an O-H group bonded to a C=C.

3. are formed from terminal alkynes with the addition of water using BH3 then H2O2.

4. are constitutional isomers that differ in the location of a double bond and a hydrogen and exist in an equilibrium with each other.

5. are compounds that contain a carbon-carbon triple bond.

6. of a terminal alkyne adds BH? to the less substituted, terminal carbon.

7. have a C=O and an additional C-H bond.

8. are formed from terminal alkynes with the addition of water using H2SO4 and HgSO4.

1) acetylide

2) enol

3) aldehydes

4) tautomers

5) alkynes

6) Hydroboration

7) Keto

8) methyl ketones

Explanation:

Acetylide anions (R-C≡C^-) is a strong nucleophile. Being a strong nucleophile, we can use it to open up an epoxide ring by SN2 mechanism. The attack of the acetylide ion occurs from the backside of the epoxide ring. It must attack at the less substituted side of the epoxide.

Oxomercuration of alkynes and hydroboration of alkynes are similar reactions in that they both yield carbonyl compounds that often exhibit keto-enol tautomerism.

The equilibrium position may lie towards the Keto form of the compound. Usually, if terminal alkynes are used, the product of the reaction is a methyl ketone.