Enantioselective Atropisomer Synthesis Via Thiolative Ring Opening Of Cyclic Diaryliodoniums

Biaryl atropisomers are a class of compounds in which their rotation around the aryl-aryl single bond was inhibited due to steric hindrance.These structures are widespread in a number of natural products,biologically active compounds,or pharmaceuticals.The synthesis of these biaryl atropisomers in a convenient and low costly way is a particular challenge.Diaryliodonium salts can serve as versatile arylating agents with a variety of nucleophiles.The cyclic diaryliodonium salts can be reacted with nucleophiles to obtain various functionalized biaryl compounds due to their unique structure.This thesis mainly focused on a Cu-catalyzed asymmetric thiolative ring opening reaction of five-membered diaryliodonium salts and potassium thioates for the synthesis of atropisomeric thioester compounds.The following two chapters were covered.The first chapter introduces the construction of biaryl atropisomers and the recent developments concerning diaryliodonium salts.At present,there are four main methods for the construction of axially chiral biaryls:the coupling of two arenes the coupling by either oxidative dimerization or cross-coupling,atropisomerism via construction of an aromatic ring(s),stereoselective functionalization of racemic or prochiral biaryls and chirality exchange.Diaryliodonium salts represent an important class of reagents among hypervalent organoiodine(?)compounds.Diaryliodonium salts can be classified into two categories:acyclic and cyclic.We have discussed the synthesis of these two different iodonium salts,the arylation reaction involving acyclic diaryl iodonium salts,and the ring opening reaction of cyclic diaryl iodonium salts.The second chapter:asymmetric ring-opening/thiolation of five-membered cyclic diaryliodoniums for the synthesis of atropisomeric 2'-iodo-[1,1'-biphenyl]-2-yl thioates.With commercially available Ph-bis(oxazoline),this thiolative ring-opening reaction usually gave high enantioselectivity.Finally,a typical P,S-ligand has been synthesized from axially chiral product without decreasing the optical activity.