Synthesis Of Prohexadione Calcium And SO₂F₂-participated Oxida-tion Of Thioethers And Tertiary Amines

This thesis mainly consists of the following two parts.Part Ⅰ:The synthesis of prohexadione calciumPlant growth regulators play an important role in the development of agriculture in the 21st century,and they can promote crop production,reduce production costs,and improve product quality.Plant growth regulators have become an indispensable part of modern planting industry.Prohexadione calcium（Pro-Ca）is one of acylcy-clohexanedione plant growth retardants,which can effectively inhibit the synthesis of active gibberellins.In the soil rich in microorganisms,the final metabolites of Pro-Ca are CO₂ and H₂O,and its half-life is short,no more than 24 hours,thus Pro-Ca is a plant growth regulator with low toxicity and no residue.It deserves to be called a green agricultural chemical and has great development potential and wide application prospects.However,there are some defects in the production of Pro-Ca in domestic workshops,such as expensive production costs,low yields and immature process route.In this part,we focused on the total synthesis of Pro-Ca.Based on the reported literatures,our work started through performing Michael addition reaction of diethyl maleate with acetone in the presence of a catalyst to generate 2-acetonyl diethyl suc-cinate A.Then A was subjected to the Claisen condensation cyclization to generate3-hydroxy-5-ethoxycarbonyl-2-cyclohexene-1-ketone B in the presence of a base.Next B underwent esterification/rearrangement reaction with propionic anhydride to provide 2-propionyl-3-hydroxy-5-ethoxycarbonyl-2-cyclohexene-1-one D.Finally D is hydrolyzed under an alkaline condition and salified with calcium hydroxide to offer the target product Pro-Ca F.In comparision with results in literatures,we made some improvement in the synthesis of Pro-Ca,including reducing one step reaction,using milder reaction conditions,and avoiding the adoptation of high temperature and high pressure conditions.Thus,our developed method shows potential application for in-dustrial production.Part Ⅱ:SO₂F₂-Participated oxidations of thioethers and tertiary aminesIn 2014,professor Sharpless reported a new type of click reaction based on hex-avalent sulfur（VI）fluorine exchange（Su FEx）.Since then,sulfuryl fluoride（SO₂F₂）,as a synthetic reagent with distinctive properties,has attracted more and more atten-tions to chemists due to the face that it could quickly realize the transformation of a variety of functional groups under mild conditions.Sulfuryl fluoride has been widely applied in the fields of drug development and biomedical materials.In the past few years,our research group has been devoting to the application of sulfuryl fluoride in organic synthesis.Our team has previously developed an efficient oxidation system SO₂F₂/H₂O₂/base for epoxidation of a variety of olefins.Based on these previous research results,the application scope of sulfuryl difluoride was broadened in this part.Since oxidation reaction is one of the most important trans-formations in synthetic chemistry and sulfones and N-oxides are indispensable motifs in pharmaceutical industry,agricultural chemicals,natural products and organic mate-rials.Inspired by our earlier experiments,we continued to investigate the behavior of oxidation of sulfides and tertiary amines with this oxidation system.It was found that the SO₂F₂/H₂O₂/base oxidation system could also efficiently oxidize sulfides to sul-fones and tertiary amine substrates to the corresponding N-oxides.The effects of re-action temperature,solvent,and the loading amounts of reagents on oxidations were optimized.