Highly Enantioselective Inverse-Electron-Demand Hetero-DielsâAlder Reactions of α,β-Unsaturated Aldehydes This work was supported by the NIH (GM-59316), with additional support from the Schweizerischer Nationalfonds zur Förderung der wissenschaftlichen Forschung (postdoctoral fellowship to K.G.), and the National Science Foundation (predoctoral fellowship to D.E.C.). We are grateful to Dr. R. Staples for carrying out the X-ray crystal structure analysis of 1.