Asymmetric Diels-Alder Cycloadditions with Chiral Carbamoyl Dienophiles

Article abstract of DOI:10.1002/hlca.19920750108

Chiral acylnitroso dienophiles 14, which were obtained from L-proline and from D-mandelic acid, reacted with cyclohexa-1,3-diene to give the expected diastereoisomers 15 and 16 (Scheme 2 and Table 1).The d.e. values for these Diels-Alder reactions were moderate; they are related to the molecular stiffness of the dienophiles.The absolute configuration of the major cycloadducts was interpreted in terms of HOMO/LUMO interactions, the approach being 'endo' and the acylnitroso dienophiles reacting from their s-cis-conformation.