Most recently, papulacandin-like spiroacetals have been accessed using this
method [192] to provide a spiroacetal-diene 402, which can then be converted to
the benzannulated spiroacetal 404 via cycloaddition with electron-deficient
alkynes, e.g., 404 (Scheme 97).
Scheme 94 Peng et al.’s Ni-catalyzed reductive cyclization approach toward spiroacetals [190]
Scheme 95 Ring-closing metathesis for the synthesis of spiroacetals
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M.A. Brimble and L.A. Stubbing