The objective of this experiment is to synthesize a a product, which combines two reactions into one. This tandem or domino reaction involves a Diels-Alder reaction and acylation and it saves work and reduces waste.
Diels-Alder reaction is a cycloaddition reaction that involves [4n+2] electrons forming a 6 member ring using a 6 electron transition state using the huckle electrong count rule. This reaction is a concerted process and is thermodynamically favoured, as it forms 2 new σ bond from the 2-π bond. It is necessary for the diene to be in the s-cis diene configuration in order for the reaction to proceed as s-trans configuration will not proceed
The reaction of the diene and dieneophile proceeds by having one as a electron rich group, while the other being the electron poor group. The normal demand is the diene being the electron rich group with electron donating functional group. While the dieneophile as the electron poor group with electrong withdrawing functional group. The inverse demand is that the diene as the electron poor group with the electron withdrawing functional group, while the dienophile as the electron rich group with electron donating functional group.
The HOMO-LUMO interaction is based on the molecular frontier orbital symmetry. It requires the same symmetry to interact so as to form new bond. If the HOMO-LUMO doesn’t have the same symmetry, the reaction cannot proceed via the diels-alder reaction.
Regioselectivity of the reaction have been identified by the HOMO-LUMO energy gap. The reaction proceeds in a way that the lowest HOMO-LUMO energy gap of the diene and dieneophile will be used to proceed in the reaction. Thus, resulting in the regioselectivity that the diene and dienophile will react in a way that follows the frontier orbital theory that the “large-large” and the “small-small” overlap (Houk rule) .
Figure of the “large-large” and “small-small” coefficient...