The Zipper-Mode Domino Intramolecular Diels–Alder Reaction: A New 0→ABCD Strategy for Steroids and Related Compounds We thank Dr. Simon Fielder (HortResearch New Zealand) and Mr. Leon Wong (University of Sydney) for preliminary experiments, Dr. Kelvin Picker (University of Sydney) for assistance with HPLC and GC analyses, and Dr. Ian Luck (University of Sydney) for 2D NMR experiments. This work was supported by The Australian Research Council and The University of Sydney.