Date | November 2019 | Marks available | 1 | Reference code | 19N.3.hl.TZ0.26 |
Level | HL | Paper | 3 | Time zone | TZ0 |
Command term | Apply and State | Question number | 26 | Adapted from | N/A |
Question
Taxol is an anticancer drug.
State the feature of Taxol that is a major challenge in its synthesis. Use section 37 of the data booklet.
Describe how the challenge in (a) was resolved by pharmaceutical companies.
Markscheme
numerous stereoisomers/chiral carbons/chiral centres/stereocentres/optical isomers ✔
NOTE: Accept exact number of chiral carbons ie 11, but do not accept just “chiral”.
chiral auxiliaries/molecule binds to reactant blocking one reaction site «by steric hindrance»
OR
asymmetric synthesis / enantioselective catalysis «producing a specific enantiomer»
OR
biosynthesis / genetically modified bacteria/microorganisms ✔
NOTE: Accept “use of a chiral auxiliary leading to «the synthesis of» the desired enantiomer”.