Nitrones and oximes of bifunctional carbonyl compounds and their reaction products with diarylborinic acids. Crystal and molecular structure of examples of five-, six-, and seven-membered boron chelates
Intramolecular cycloaddition of chiral α-acyloxynitrones to in situ generated α,β--unsaturated esters occurs with very high diastereoselectivity to afford useful precursors for the synthesis of β-lactamantibiotics.