New classes of ligands for asymmetric synthesis

This thesis is divided into six chapters. The first is a review of general asymmetric synthesis, and considers in detail the palladium catalysed allylic substitution reaction, the 1,4-conjugate addition and the Heck reaction. The second deals with our general synthetic approach to the chiral ligands. Here we synthesized a range of ligands derived from chiral amino alcohols condensed with aryl and aliphatic ketones. We also synthesized chiral sulphur imine and phosphorus imine ligands. The third deals with applications of the ligands in the above reactions, and discusses the most successful ligands. In the palladium catalysed allylic displacement reaction, the sulphur imine ligands were the most successful ligands with ee of 96%. In the case of the 1,4-conjugate addition of diethylzinc to cyclic and acyclic enones, we were able to achieve excellent results using the phosphorus imine and the S–N ligands derived from pseudoephedrine and ketones, ee of >99% were obtained. Chapter four deals with asymmetric sulfoxidation and the effect of electron donating and withdrawing groups on the sulfoxidation. Here we demonstrated the inductive influence of the substituent on the ee of the sulfoxide. Chapter five deals with the conclusion. The sixth part of this thesis deals with the experimental procedures undertaken in this work.