Thianthrenium Salts Enabled C-C/P Bond Forming Reactions And Related Mechanistic Studies

Organic sulfonium salts([R~1R~2R~3S]~+X~-)are a type of compounds in which the positively charged sulfur atom is bonded to three organic substituents with a non‐coordinated counter anion.Thianthrene sulfonium salts is a novel class of excellent electrophiles,which can be easily prepared.Compared with traditional electrophiles(such as aryl halides,alkenyl halides).Sulfonium salts have the advantages of high selectivity and efficiency which make them have huge potential applications in the field of organic synthesis.In this project,thianthrene sulfonium salts are used as an electrophile for highly selective phosphination with diarylphosphines,as well as arylation with arylboronic acids.In addition,the related mechanisms are also investigated.The main contents of this thesis are as follows:1.The reaction of aryl thianthrene sulfonium salts as an electrophile with diarylphosphines undergoes highly efficient phosphonation via selective cleavage of the C-S bond of aryl sulfonium salts.In the absence of catalyst,the reaction undergoes phosphinative ring-opening exclusively via the cleavage of an endocyclic C-S bond of thianthrene skeleton.The use of a palladacycle catalyst under otherwise the same conditions enables the phosphination via the cleavage of an exocyclic C-S bond with significantly higher speed.The reaction has the characteristics of mild conditions,wide versatility and high selectivity.This protocol provides an efficient way for highly selective installation of diarylphosphino groups onto a wide scope of arenes,heteroarenes,and complex molecules and gives a new method for synthesizing triarylphosphine compatible with various sensitive functional groups.2.The reaction of alkenyl thianthrene sulfonium salts as an electrophile with aryl boronic acids underwent highly arylation.The use of a diene ligand enables the reaction undergoing selective cine-substitution giving styrene derivatives,while the use of a biphosphine ligand renders ipso-substitution yielding internal alkenes.And by means of deuterium labeling experiments,a reasonable reaction mechanism was proposed.In summary,this project has successfully achieved the highly selective phosphination of aryl thianthrene sulfonium salts with diarylphosphine and the highly selective substitution of alkenyl thianthrene sulfonium salts with aryl boronic acid under the action of transition-metal-catalysts.And this protocol provides a new idea for a new type of carbon-carbon/phosphorus bonding reaction.