Keywords

DBU-promoted dehydrobromination, 1, 1-difluoro-1, 3-dienes synthesis, Triazolinedione cycloadditions, Cycloaddition reactivity of difluorodienes, Trifluoromethyl formation side reaction

Abstract

The title 1,3-dibromo- l, l-difluoro compounds are dehydrobrominated in the presence of l,8-diazabicyclo[5.4.0]undec-7-ene (DBU). Reaction of simple saturated dibromides with DBU at 25 °C affords moderate yields of monoelimination products in which the reaction is 100% stereoselective and regioselective. Highly conjugated dienes are synthesized at mild reaction conditions in contrast to simple alkyl or pentafluorophenyl dienes which are inaccessible via a double dehydrobromination reaction due to the unexpected formation of trifluoromethyl compounds. Aromatic gem-difluorodienes react with 4-phenyl-1,2,4-triazoline-3,5-dione and a mechanistic experiment demonstrates the relative reactivities of the isomers of 1, l-difluoro-4-phenyl-1,3-butadiene in a Diels-Alder reaction. The unfluorinated analogue of 1, l-difluoro-4-phenyl-1,3-butadiene reacts completely and rapidly with maleic anhydride while 1,1-dilluoro-4-phenyl-1,3-butadiene remains inert towards this classical dienophile.

Notes

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Graduation Date

1991

Semester

Spring

Advisor

Elsheimer, Seth

Degree

Master of Science (M.S.)

College

College of Arts and Sciences

Department

Chemistry

Format

PDF

Pages

111 pages

Language

English

Length of Campus-only Access

None

Access Status

Masters Thesis (Open Access)

Identifier

DP0028084

Subjects

Arts and Sciences -- Dissertations; Academic; Dissertations; Academic -- Arts and Sciences; Elimination reactions; Organofluorine compounds--Synthesis; Diolefins; Diels-Alder reaction; Pericyclic reactions

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