1. Published Online February 10 2011
Science 18 March 2011:
Vol. 331 no pp
DOI: /science

2. Introduction

3. The precise spatial arrangement of amino acid and cofactor subunits in a highly dynamic setting is the key to enantioselectivity achieved by enzymes.
It’s challenging to switch the enzyme’s selectivity, because the chirality of the active site environment is set by the inherent chirality of the constituent amino acid building blocks.

4. Desired Molecule

5. Hydrogen bonding donor
Brønsted base
Work as bifunctional organocatalyst
The basic principle of chiral catalytic system by exploiting the unique dynamic stereochemical features of unidirectional rotary molecular motors.

6. 57%
77%
50%
15%

7. A B

8. Characterization

9. distinct isosbestic points

11. Application to Catalyst

12. A: (2R,2’R)-(P,P)-trans-1 was employed.
B: (2R,2’R)-(M,M)-cis-1
C: (2R,2’R)-(P,P)-cis-1

13. (2R,2’R)-(P,P)-trans-1
(2R,2’R)-(M,M)-cis-1
(2R,2’R)-(M,M)-trans-1
(2R,2’R)-(P,P)-cis-1
HyperChem 8.0 (HyperChem(TM), Hypercube, Inc., 1115 NW 4th Street, Gainesville, FL 32601, USA)
The motor units of the four isomers were built from the crystal structures of the first generation motors.

14. Side view
※ Cyclohexenone has prochirality which affect product’s chirality through reaction.
(2R,2’R)-(M,M)-cis-1
(2R,2’R)-(P,P)-cis-1

15. Added C: (2R,2’R)-(P,P)-trans-1
D: (2R,2’R)-(M,M)-cis-1
E: (2R,2’R)-(P,P)-cis-1
83% yield after 15h
50% 7%

17. Thank you