exo- and Enantioselective Diels-Alder Reactions: Pyrazolidinone Auxiliaries as a Means to Enhanced exo Selectivity

Abstract

Achiral pyrazolidinone auxiliaries have been investigated in exo- and enantioselective Diels-Alder reactions. The effect of pyrazolidinone N-1 substitution and chiral ligand identity were studied in Yb(OTf)₃-catalyzed exo-selective Diels-Alder reactions. An appropriate choice of pyrazolidinone auxiliary and Yb(OTf)₃/Pybox chiral Lewis acid led to moderate exo selectivity and high enantioselectivity for the exo-cycloadduct.

Key words

Diels-Alder - exo-selective - enantioselective - pyrazolidinone - chiral Lewis acid

References and Notes

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12

The identity of the exo and endo adducts was established by NMR spectroscopy. Additionally, the products were converted into known benzyl esters.