Cyclization, Nozaki-Hiyama-Kishi reaction

Pietruszka [75] reported the total synthesis of a series of solandelactones (A-H) by the coupling reaction of the lactone 78, the key intermediate, with side chains 79 and 80 (Scheme 5.27). Lactone 78 was prepared by cyclization of the seco-acid 77 under Yamaguchi conditions in good yield (85%). Finally, the Nozaki-Hiyama-Kishi coupling of the unsaturated lactone aldehyde or its saturated counterpart with the iodide 79 or 80 afforded solandelactones A-H in good yields as separable diastereomeric mixtures (ratio 2 1). 

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