Teacher:In this task, you will be given a passage to read. A fill in the blank question will be given to you. Your answer should fit the blank appropriately.
Teacher: Now, understand the problem? Solve this instance: The development of an enantioselective ( i.e. yielding an enantiomeric excess , which is labelled as ee ) variant of the Johnson Corey Chaykovsky reaction remains an active area of academic research . The use of chiral sulfides in a stoichiometric fashion has proved more successful than the corresponding catalytic variants , but the substrate scope is still limited in all cases . The catalytic variants have been developed almost exclusively for enantioselective purposes ; typical organosulfide reagents are not prohibitively expensive and the racemic reactions can be carried out with equimolar amounts of ylide without raising costs significantly . Chiral sulfides , on the other hand , are more costly to prepare , spurring the advancement of catalytic enantioselective methods . fill in the blank : The development of an __________________ ( i.e.
Student:
enantioselective