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Chemistry Forums for Students => Organic Chemistry Forum => Organic Chemistry Forum for Graduate Students and Professionals => Topic started by: medist on February 28, 2014, 01:36:50 PM

Title: reactivity explanation
Post by: medist on February 28, 2014, 01:36:50 PM

Can some one help me in explaining the higher reactivity of 4-Phenyl-1,2,4-triazoline-3,5-dione in cyclo addtitions than any other dienophiles?

Title: Re: reactivity explanation
Post by: TheUnassuming on February 28, 2014, 02:16:24 PM

In general what makes a dienophile better or worse (electronically) to engage in cycloadditions (could the substitution of nitrogens vs carbons or the benzyl vs esters make the necessary shift to the HOMO)? 
Do you think steric constraints of being in a ring could shift the Pi* orbitals to a more favorable position?