Catalytic Enantioselective Diels-Alder Reactions

Theoretical studies were performed on BH3,BF3 and BLA acting as catalysts in the [4+2] cycloaddition reaction of cyclopentadiene and methacrolein. All three catalysts are effective in catalyzing the reaction by lowering the LUMO energy of the dienophile. BLA, in particular, is an enantioselective catalyst specifically designed for α-substituted dienophiles. The enantioselectivity of the catalyst could be understood from the transition state assembly, proposed separately by Corey and Yamamoto and calculations show that Corey’s model leads to an energetically preferred pathway. In the hierarchy of carbon-carbon bond construction, the Diels-Alder reaction has attained a preeminent position. This cycloaddition process allows for the stereoselective formation of cyclohexene rings possessing as many as four stereogenic centers.Th