Alkene Metathesis

Question 1

intermolecular

Answer 1

hard to control, need to choose cross-partners carefully to prevent unwanted products

Question 2

Grubbs metathesis catalysis

Answer 2

ruthenium and air stable

Question 3

reactivity of grubbs catalyst

Answer 3

Olefins>Acids>Alcohols, water>Aldehydes>Ketones>Esters, amides

Question 4

use of N-heterocyclic carbene ligand

Answer 4

good s-donor, acts as pre-catalyst giving Ru centre with 14e and empty coord site

Question 5

uses of ring closing metathesis

Answer 5

reversible cyclisation of macrocycles, favoured entropically but needs high dilution to prevent dimerisation, oligomerisation or polymerisation

Question 6

tandem ring opening polymerisation - ring closing metathesis

Answer 6

Grubbs forms active catalyst with ethene then RCM to give most thermodynamically stable product