Synthesis of the (+)-C26–C40 Domain of the Azaspiracids by a Novel Double Intramolecular Hetero-Michael Addition Strategy This work was supported by the United States National Institute of Environmental Health Sciences (NIEHS; grant number ES10615), NIH, and by Bristol-Myers Squibb (CJF). Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIEHS, NIH, or BMS. We thank Dr. A. B. Dounay and Dr. G. Florence for critical reading of the manuscript.