Synthesis Of Thioethers Via Oxidative Coupling And Csp~3-H Functionalization

As an important branch of organic chemistry, organosulfur chemistry is always a research focus for chemists.Thioether derivatives serve as a significant part among all organosulfur compounds for their special properties, which makes them widely used as important intermediates and functional molecules in pharmaceutical synthesis,biochemistry and material science. Exploring a novel methodology for thioethers synthesis is important in basic science and production.Oxidative coupling is a significant innovation in methodology in the past decade and a new concept against the classic cross coupling, it surpasses the innate ideas of "electrophile & nucleophile" to construct molecules in retrosynthesis analysis by a replacement of "two nucleophiles".C-H functionalization is a synthetic strategy to construct new C-C and C-X bonds by cleavage of the C-H bond and introduction of new functional groups.This dissertation focuses on one-step synthesis of thioethers using oxidative coupling as guiding conception and C-H functionalization as strategy. Compared to the traditional ones, these procedures are more efficient and easier to handle, which shorten the synthesis process and reduce the waste with a higher atom economy, totally matching the conception of "green chemistry".The content of this dissertation include three parts:1. Copper-catalyzed direct oxidative alkenylation of thioethers via Csp3-H functionalization to construct allylic thioethers for the first time. Mechanism study implies this transformation is a radical process and iodine palyes a key role for β elimination to reform alkenes.2. Iodine catalyzed oxidative coupling between 1,3-diketons and thiophenols to form β-dicarbonyl thioethers for the first time. Mechanism study implies this transformation is a radical substitution pathway instead of a nucleophilic one.