Dramatic Diastereoselectivity Differences in the Asymmetric Ene Reactions of Triazolinediones and Singlet Oxygen with Chiral 2,2-Dimethyloxazolidine Derivatives of Tiglic Acid
diastereoselectivity in the enereactions of triazolinedinone and singlet oxygen with chiral oxazolidine or oxazolidinone derivatives of tiglic acid depends both on the chiral auxiliary used and the size of the attacking enophile. While chiral 2,2-dimethyloxazolidine amides of tiglic acid give with triazolinediones TAD only one single ene adduct, the corresponding chiral oxazolidinone derivatives (Evans′