University:
University of Houston
Course:
CHEM 1322 | Honors Fundamentals of Chemistry 2
Academic year:

2022
Views:

459

Pages:

1
Author:

albulaastediasjn4

Dienes: Relative Reactivities with Maleic Anhydride: Huisgen, R. “Chemistry of the Alkenes,” p. 921 NEt 2 Ph O OMe > > TMSO TMSO NEt 2 > > > 1400 Ph OEt NHCOX Ph > 110 OAc MeO ~ ~ ~ ~ > 12 5 CO2H Ph Cl ~ > 3 ~ ~ 2 Cl R ~ > > 2 R >> 1 0.1 R ~ ~ Cl Cl Cl Cl Cl 0.00016 (R is small) Completely Unreactive: t-Bu Cl t-Bu Ph t-Bu Cl Diene reactivity is increased by: (A) e--donating groups, (B) planarity of the system, and (C) ability to adopt an s-cis conformation Dienophiles: Relative Reactivities with Cyclopentadiene: Houben-Weyl 5/1C p. 1026 Very Reactive Dienophiles: N N NC N Ph CN COCl > > NC CN > > NC CN ClOC > O > 4x 5x 10 5 4x 10 4 O 900 5000 90 Mono-Activated Dienophiles COCl > 20 CHO > 10 COR > CO2R CN ~ CN >> 1 5 -another series: CHO 1 > CHO 0.08 > CN O 10 7 CN > CN O "record holder" O O O > CHO 0.005 Reactive Unactivated Dienophiles Dienophile reactivity is increased by: (A) electron-withdrawing substituents, (B) a weak π-bond, and (C) release of ring strain. 1 0.1

Relative Reactivity in Normal Electron-Demand Diels-Alder Reactions

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