UCLA

Chapter 1

A fundamental understanding of the thermodynamics and kinetics of mech-anically interlocked molecules, such as [2]rotaxanes, will contribute to a more rational design of new molecular machines. This Chapter describes the influence of chemical modifications and the role of the physical environment on the ground state thermo-dynamics and the shuttling and switching kinetics of several tetrathiafulvalene- and 1,5-dioxynaphthalene-containing [2]rotaxanes. A comparison between the properties of these bistable rotaxanes and model host-guest complexes of the corresponding π-electron donating recognition units with the π-electron accepting cyclophane, cyclobis(paraquat-p-phenylene), has been made, resulting in useful guidelines for the design of new bistable rotaxanes with specific, desirable physical performances

Chapter 2

Palladium-catalyzed cross-coupling reactions are well documented in the vast chemical literature but homocoupling reactions have not yet been truly explored to the same extent. Chapter 1 describes and explores recent advances of palladium-catalyzed homo-coupling reactions.

Chapter 3

An efficient and straightforward route toward unsymmetrical macrocyclization producing (E,E)-diene macrocycles was developed using 1-(E)-alkenylboronate esters and palladium(II). When 1-(E)-alkenylboronate esters were treated with a catalytic amount of PdCl2(PPh3)2 and chloroacetone as the oxidant in high dilution in methanol, formation of (E,E)-dienes was successfully achieved. For example, synthesis of 14-, 15- and 16-membered (E,E)-diene macrocycles were obtained in good yields and as single geometrical isomers. Overall, this protocol is synthetically more efficient than a typical palladium(0)-catalyzed coupling of substrates containing both electrophilic and nucleophilic end groups.

Chapter 4

An efficient and straightforward route toward unsymmetrical macrocyclization producing (Z,Z)-diene macrocycles was developed using 1-(Z)-alkenylboronate esters and palladium(II). When 1-(Z)-alkenylboronate esterss were treated with a catalytic amount of PdCl2(PPh3)2 and chloroacetone as the oxidant in high dilution in methanol, formation of (Z,Z)-dienes was successfully achieved. For example, synthesis of 8- and 14-membered (Z,Z)-diene macrocycles were obtained in excellent yields and as single geometrical isomers. Overall, this protocol is synthetically more efficient than a typical palladium(0)-catalyzed coupling of substrates containing both electrophilic and nucleophilic end groups.