CHE 3331 Lecture Notes - Lecture 2: Orbital Hybridisation, Electrophile, Pi Bond
Document Summary
This mechanism is concerted all arrows are pushed at once. May contain electron donating groups: o-r group, r group, electron rich. Typically contains electron withdrawing groups: cn, cooh, other carbonyls (ketone, amide, ester, etc, electron poor. For every pi bond, there are two possible molecular orbitals: : bonding orbital, : antibonding orbital, more bonding interactions than antibonding , more antibonding interactions than bonding , each mo can hold two electrons. The lumo of the dienophile favorably overlaps with the homo of the diene. This only works with the diene in the s-cis position. 4 carbons switch from sp2 to sp3 hybridization. 1,2 (ortho) and 1,4 (para) addition products are the major products: you almost always do not generate 1,3 (meta) Diene: always place any electron donating groups (edg) in either 1 or 3 position to place the most electron density at 4. Always place ewg at 6 in order to have least electron density at 5.
