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Title:Syntheses and Reactions of Novel Bicyclic Aryldialkoxybrominane and Aryldialkoxyiodinane Oxide
Author(s):Nguyen, Tuyen Thanh
Department / Program:Chemistry
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Chemistry, Organic
Abstract:The synthesis of 4-methyl-2,6-bis{1-hydroxy-1-(trifluoromethyl)-2,2,2-trifluoroethyl}aniline (2) in several steps from 4-methyl-2-{1-hydroxy-1-(trifluoromethyl)-2,2,2-trifluoroethyl}aniline (5) provides a necessary precursor for the incorporation of a stabilizing tridentate ligand in compounds of hypervalent nonmetallic elements.
Oxidation of 4-methyl-2,6-bis{1-hydroxy-1-(trifluoromethyl)-2,2,2-trifluoroethyl}bromobenzene (7a) with bromine trifluoride gives 10-methyl-3,3,7,7-tetrakis(trifluoromethyl)-4,6-benzo-1-broma-2,8-dioxabicyclo{3,3,1} octane (8a), the first stable and well-characterized tricoordinate organobromine(III) species. The structure of brominane 8a was determined by X-ray crystallography to reveal a pseudo trigonal bipyramidal geometry around the bromine atom with an O-Br-O angle of 167.6(DEGREES). The X-ray structure of the iodine analogue of 8a, compound 10a, is also reported (O-I-O, 158.2(DEGREES)). Both halogenanes exist as dimers in their crystal lattice with intermolecular Br-O distances of 2.97 (ANGSTROM) and I-O distances of 3.00 (ANGSTROM).
Brominanes 8 behave as oxidizing reagents toward various substrates such as iodide, bromide, thiophenol, and aniline, and as dehydrogenating reagents toward 9,10-dihydroanthracene and tetralin. Reaction of brominane 8b with potassium hydroxide in tert-butyl alcohol affords oxygen, isobutylene and the potassium salt of 7b. Addition of pentafluorophenyllithium to 8b gives aryl ether 12.
Oxidation of iododiol 6b with bromine trifluoride affords difluoroperiodinane 4b which undergoes hydrolysis to give iodinane oxide 5b, which is stable for an indefinite period at atmospheric condition. Iodinane oxide 5b is a strong oxidizing reagent. Treatment of iodinane oxide with trifluoroacetic anhydride gives periodinane 10, while addition of trifluoroacetyl trifluoromethanesulfonate (TFAT) or triflic acid gives periodonium ions. Addition of difluoroperiodinane 4b with TFAT also gives periodonium ion. These periodonium ions are stable at room temperature but they are moisture sensitive.
Issue Date:1983
Description:127 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1983.
Other Identifier(s):(UMI)AAI8309990
Date Available in IDEALS:2014-12-15
Date Deposited:1983

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