Based On The Sulfone Grouping Reaction Of Alkenes And Alkynes

Organic sulfone compounds have a wide range of applications in chemical research,pharmaceutical chemistry,materials science and related cross-cutting areas.Sulfone structural unit is usually one of the key structural skeletons of natural products,biologically active compounds and drug molecules.In particular,alkenyl sulfone,alkynyl sulfone and benzofuran organic sulfone structural units exhibit a broad range of biological activities.Most of previous synthetic methods require cumbersome operation steps,relatively harsh reaction conditions and the use of metal catalyst,which limit their applications in synthetic chemistry.Therefore,the development of simple,convenient and effective methods for the synthesis of these compounds is still highly desirable.Thesis is mainly focus on the development of new methods for the construction of various E-vinyl sulfone,alkynyl sulfone and benzofuran sulfones via sulfone olefins,alkynes,and 1,6-enynes under metal-free conditions.The paper contains the following three parts:?1?A facile I₂O₅-mediated direct oxidative coupling of aromatic alkenes with thiols toward vinyl sulfones has been developed under metal-free conditions.This methodology provides a convenient and efficient approach to various E-vinyl sulfones from readily available starting materials with excellent regioselectivity.The present oxidative coupling reaction not only provides a new way to construct E-vinyl sulfones,but also expands the scope of functionalization reactions of alkenes with thiols.?2?A facile and efficient one-pot method has been developed for the construction of alkynyl sulfones via direct cross-coupling reaction of aryl alkynyliodines and arylsulfinic acids.The present transformation could be accomplished under catalyst-and additive-free conditions,providing a series of alkynyl sulfones in moderate to good yields with favorable functional group tolerance.?3?The oxidative cyclization of 1,6-enynes with sulfonylhydrazides leading to sulfonylated benzofurans has been developed under metal-free conditions.This reaction produces a series of sulfone-containing benzofurans with good functional group tolerance by simply using of I₂O₅ as the additive and TBHP as the oxidant,respectively.Preliminary mechanism studies indicated that the present reaction might undergo via the sulfone of alkyne,radical cyclization,oxidation,and hydrolysis process.This method provides a novel and efficient approach to access sulfonated benzofuran compounds.