Photostimulated tert-butylations of a,b-unsaturated nitriles, cyclizations of 1,6-dienes and olefinic nitriles, and homolytic aromatic alkylations

dc.contributor.advisor Glen A. Russell Chen, Ping
dc.contributor.department Chemistry 2018-08-23T17:07:33.000 2020-06-30T07:15:42Z 2020-06-30T07:15:42Z Wed Jan 01 00:00:00 UTC 1997 1997
dc.description.abstract <p>[alpha],[beta]-Unsaturated nitriles undergo radical chain addition reactions with tert-butylmercury halides in the presence of iodide ions. The mercury adduct products are formed in high yields and can be converted to the reductive alkylation products with NH4+ or by NaBH4. The addition reaction involves the attack of the adduct radical upon the ate complex, t-BuHgI2-. Proton donors also promote the reactions by protonating the adduct radicals to form keteniminyl radicals cations which accept an electron from t-BuHgI2- to produce the alkylation products. Acrylonitrile, crotononitrile and fumaronitrile give nearly quantitative yields of the products in DMSO via photolysis or even in the dark at room temperature. Three-component condensation reactions occur for mixtures of acrylonitrile/t-BuHgI and reagents such as CH2=CHCH2Br or CH2=CHCH2SPh or upon further reaction of the mercury adducts with I2, NBS, PhCH=CHI, PhSeSePh, or iminium ions;Cyclization reactions of 1,6-dienes with t-BuHgX have been investigated. A radical chain process provides the cyclized organomercurials via 5-exo mode cyclization. Cis and trans isomeric cyclized mercury compounds are obtained with the cis-isomers preferred. The measured initial kinetic chain length for the substrates are 3-10. Photolysis of the mercury compounds with PhSSPh leads to the corresponding sulfides. Allyl vinylphosphonates react with t-BuHgX very readily. However, the cis/trans product ratio is 1:1;Alkylmercury halides are very suitable reagents for alkylation of electron-deficient aromatics. In the presence of Dabco (1,4-diazabicyclo (2.2.2) octane), the disubstituted benzenes undergo a regioselective radical alkylation reaction. For 1,3-dicyanobenzene, the initial kinetic chain length is 22 and not only the mono-alkylated but also the dialkylated product is produced in high yield. With larger groups meta or para to a cyano group such as -CHO and -CO2Et, the second alkylation is inhibited. Dabco promotes the chain reaction by removing a proton from adduct cyclohexadienyl radical. The radical anion formed is oxidized by t-BuHgX to afford the product and regenerate t-Bu·.</p>
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dc.identifier.articleid 12782
dc.identifier.contextkey 6510259
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath rtd/11783
dc.language.iso en
dc.source.bitstream archive/|||Fri Jan 14 18:58:00 UTC 2022
dc.subject.disciplines Organic Chemistry
dc.subject.keywords Chemistry
dc.subject.keywords Chemistry
dc.subject.keywords Organic
dc.subject.keywords Organic chemistry
dc.title Photostimulated tert-butylations of a,b-unsaturated nitriles, cyclizations of 1,6-dienes and olefinic nitriles, and homolytic aromatic alkylations
dc.type article
dc.type.genre dissertation
dspace.entity.type Publication
relation.isOrgUnitOfPublication 42864f6e-7a3d-4be3-8b5a-0ae3c3830a11 dissertation Doctor of Philosophy
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